The Photographers' Assistant.

        The masters plead inefficiency as excuse for low wages, and bewail the Jack of good assistants.
        The assistant pleads lack of means and absence of encouragement as excuse for inefficiency. Which is right?
        The position of the average assistant in the average photographic business has been in the part anything but an enviable one from any point of view. He is expected to handle successfully a large range of materials which are sensitive to many influences, often in circumstances and with apparatus that are in them handicaps to the production of good work. The knowledge and skill required to cope with the never ceasing stream of technical problems are perhaps greater than in any other craft, not only because of the existence of those problems, but also because the photographic business is not 10 sharply sub-divided into its many branches, and an assistant may be called upon at any time to do work of a kind quite outside his Ordinary job, and is expected to produce results equal to those of a man whose regular practice it is.
        That roughly suggests what is expected of the assistant as regards hi work. Usually he is required also to keep an appearance above that of a wage-earner, such as a mill-hand, letterpress printer, or bricklayer, and to cultivate the affability of speech and manner which is perhaps the principal asset of the successful doctor or lawyer. The dark-rooms in which many assistants spend nearly a third of their lives and most of the hours of daylight often are little better as regards health or comfort than the workrooms of many yean ago described so vividly by Charles Kingsley in "Alton Locke."
        So that compared with other crafts, quite apart from the rate of wage, photography exacts more, and offers less. That the average rate of pay, and consequently the social position, of the photographer's assistant, is comparatively very low is a fact, obvious and admitted. What are the natural consequences of this?
        I think that assistants may be divided broadly into two classes. The first class has caught the fascination which undoubtedly exists in photography for anyone with average intelligence and a little imagination. If to these qualities the assistant adds ambition he usually becomes the master-man eventually, but the business knowledge essential to success is not easily gained during the assistant period. The second class, by far the larger one, and probably still more increased by war recruits to the business, comprises those who are by nature slack, unintelligent, or unambitious, and those for whom the handicaps and discouragements incidental to the struggle for success in such an exacting calling have proved too great.
        The worker who has struggled to efficiency in spate of the many difficulties in his path still finds that adequate reward is not easy to get. He may have worked for a low wage for the chance of getting special experience, but the last rate of pay earned is still too often taken as the measure of a man's value. Many employers, far too many, are imbued with the idea that if they only advertise and back, advertise and sack, often enough they will eventually secure for the inefficient's wage either one of the skilled men willing to work for little money to increase his experience, or one of the disappointed ones for still less. The result is that the latter either recover a bit of their ambition or sink entirely to the level of the man who only just enough and that hardly wells enough, to earn his salt. The ambitious man very quickly picks up what he wants to learn and moves on, so that this type of employer is seldom suited for long. Another type of employer has greatly increased of late years in the shape of the "company shops," which turn out large quantities of inferior work by semiskilled workpeople on the "factory" principle. The wages offered by these firms to inefficient are often much higher than those paid by firms of standing to expert assistants.
        I have tried to show that the conditions fostered by employers tend to discourage a man from becoming efficient, besides offering him little reward if he overcomes the difficulties, often needless and stupid, placed in the way of his improving his ability. That there is "plenty of room at the top" is not true of photography, for there are always vacancies for those willing to accept a low wage; but a man who has made a study of his business and knows his real ability is often turned down in favor of one who will work for a little less money. It does not seem to occur to the average employer that the careful and conscientious worker can easily save the extra pay he asks, both in time and material as well as in quality of output. Yet we find the employers continually bewailing the difficulty of finding efficient assistants!
        Make the life of a really good assistant worth living, by giving him tools and material that will be a pleasure to work with, in clean and healthy workrooms, and pay him a wage that will permit him to have a decent home that he can take a pride in, as well as to have a hobby or two and the time to enjoy them in, and there will very soon be an army of assistants making themselves efficient. A few employers have rebased this, and find it pays them well to pay their staff well.
        Among those about to return from the Army employers will be looking for experienced assistants. Let me tell employers of a spirit that they may expect to find in these men, which I have noticed spreading among all ranks during the past year or more. It is a. spirit of antagonism to injustice, and is perhaps a sort of reaction against the harsh "militarism" and so-called "discipline" of the Army. It is not rebellious or antagonistic to authority, but men have been taken out of their ruts, and have been living a life summarized by "look after you, for no one else will." Living hugger-mugger with men of all classes, Jack finds out that he's as good as his master, and often better. This has resulted in a spirit of camaraderie flavored with independence, which shows itself outwardly among the men by willing work so long as those in authority do not "come it," and by obvious resentment and often by obstructionist methods if they do. Per contra officers and N.C.O.s find it pay better to recognize this new spirit, which has replaced the old "shirk while he isn't looking" idea and there is increased mutual confidence and respect. Men are told, as recruits, that the Army can tame even lions, but it has gone further, and is taming even sergeant-majors.
        This new feeling of self-reliance and impatience with injustice, if it can show itself so strongly in the most autocratic institution we have, is not likely to be shed when the khaki is left behind.

D. CHARLES.

Progress Of Pictorial Photography.

A booklet of which we have recently been the recipients contains an interesting review of the present tendencies in pictorial. Photography in the shape of an interview with Mr. Clarence H. White, one of the prominent exponents of art-through the Medium of the camera in the United States, and the director of a school of photography founded for the purpose of providing systematic instruction in this branch of work. It is not so many years ago that Mr. White appeared before the British photographic public is one of the young men enthusiastic in establishing altogether new ideals and new forms in pictorial photography. The American school, as it was then styled, came in for a large measure of derision, but it has been easy to taco its influence in the exhibitions of pictorial work during the past ten or fifteen years. Equally there has been observed some abandonment in the more extreme features which characterise the early work of these American pioneers; and therefore it is interesting to have Mr. White's conspectus of a stage of progress in which he has taken a notable share. EDS. " B.J "]



“Mr. White, I want to ask you whether you think that pictorial photography has made substantial, or any, progress in America caring the past year? “
«I believe that pictorial photography is progressing, but its progress is not to be expressed in terms of a year. Pictorial photography is expressed more or less in terms of epochs. My observation is that there has been a big growth in well, I cannot say exactly in a year, but in the last four or five years. I may say hat this grows is evident even in places remote and in places there we once heard practically nothing of pictorial photography out find now large group, of very active and earnest workers, most if them producing very high-class work."
"What has been the influence pictorial Photographers of American on photography during the past year? »
“The influence has been one of substantial encouragement. For One thing we have sent to various museums, important exhibitions If photographs. Here is a little incident that came to me a few lies ago that might help to answer your question. A young woman, a member of our organization, was in the Cleveland Art Museum. While she was in the room where our photographs were being shown she saw the director approach with an English artist, and she overheard this conversation. Ashe passed the door the director asked the artist to go in with him and see the exhibition of photographs. The artist protested that he did not care to go in and that he did not believe in it, and that he did not think there was anything in pictorial photography. The director quietly insisted on his going in, saying that he felt very decidedly that there was more real enthusiasm manifested in this exhibition of photographs than there was in a group of etchings that was shown in another room. This is significant of a change of attitude toward photography as an art, and there are about sixteen different museums in which this state of things is being revealed. I have in mind the Newark Museum. They had a collection of these photographs displayed in a most beautiful way in the Newark Public Library, and along with it they showed copies of all known magazines devoted to the subject, with portfolios representing examples of the work of photographers in Europe, and a person who came to view these pictures could then turn to these magazines or portfolios and study them."
“What effect would you say war conditions have had on pictorial Photography? »
“In America the effect on pictorial photography has been, I would say, rather to dampen enthusiasm or to discourage it. There has been a feeling that all activities should be directly connected with the war, and that photography should share in this; that pictorial photography should be devoted to placarding the war or the spirit of the war a sort of war propaganda, rather than purely pictorial work. Abroad, one of the interesting things I have nosed in connection with the catalogue of the Royal Photographic Society exhibition, the oldest photographic organization in the world and the most important one, is that the exhibition reveals very little of war-time activities. They are showing pictorial photographs, technical photographs, Auto chromes, and every branch of photography. The pictorial section had no particular bear the war nor had the Auto chrome or the scientific section. The selection of forty-nine prints loaned by members of the British Military Service formed the only contribution directly pertaining to the war. In the advertisements in this catalogue there was practically no reference to the war and an advertisement of a photographic school in connection with the Regent Street Polytechnic contained no mention "of a war course, but did mention conspicuously their pictorial work."
«Has any development along the lines of what we might call cubistic art got into pictorial photography?”
«Yes, it has gotten into photography to a slight extent, but I am loth to call it cubism or any similar ism. The development of modern art. I think, is in the direction of construction and construction picture construction applies to photography as definitely as it apples to painting and other art. Indeed, a great feeling of the need of this has expressed itself in connection with photography."
"What do you mean by the ' construction ' of a picture? Anything different from the rules of composition as usually understood by artists”
“The rules of composition as usually understood have been too narrow. We might say there are no rules but there are certain fundamentals. These fundamentals have been made to apply in a great variety of ways. Take this print, for instance (Mr. White took up a photograph showing some peculiar architectural effect) here is a little of what we might call cubism in modern photography
We first look at it, and we get pleasure from the play of light and dark n the object. It produces a sense of satisfaction to the eye, and yet when we examine it more closely we feel that the artist has violated the roles of what might be called composition. We must construct oar rules of composition from examples rather than make the construction that is demanded by our art out of formal rules."
“Can commercial or professional photography assimilate pictorial principles? »
«I believe commercial or professional photography should be pictorial. Pictorial photography is (imply a name applied to photography that really has, or should have, construction and expression.”
«Has colour photography a future? Has the Auto chrome a future? "
«I feel that the Auto chrome has already demonstrated its position and the colour print will eventually take a definite position. Processes will be simplified in much a way that it can be used more successfully by the amateur, and the amateur’s work and enthusiasm are necessary to its development."
“Has platinum paper been in the market during the past year?"
«Black platinum paper practically disappeared from the market, but sepia platinum paper has been obtainable."
“What is the best substitute for platinum paper?"
"The Barmen Journal or Photography a recognized technical publication devoted to photography, has said that printing de lure should be done on platinum or palladium, which are absolutely permanent papers. Carbon is also in be clawed with these as permanent There is no real substitute for these papers, and I trust that they will eventually be again available "
"What do you think of the bromide papers made on Japan tissue?'
“I think they have produced very beautiful results."
"Is bromide paper the best available paper of the future for pictorial effects?"
"Bromide prints are most beautiful, and the quality of some bromide prints that we see is such that it is difficult to distinguish them from platinum, which is surely the greatest compliment we can pay them."
"Can the bromoil process ever be used except by expert workers with a gift of patience?"
"I find that the bromoil process is often used by people who are not experts, but amateurs with a desire to achieve a good photographic result. To be an expert, of course, would help very materially in producing this result. There are very few expert bromoil printers."
"Has the ' gum print ' passed? If so, what has taken its place as a medium of expression for workers who think they have something to express that is beyond straight photography? "
"I think the ' gum print' has not passed and is not likely to, but to become really of greater interest as time goes on."
"Are as many gum prints' seen in exhibitions now as formerly? »
“No. The reason. I think, is that some of the best workers in the medium are not interested particularly in showing their work in exhibition”
Mr. White here turned to some choice gum prints that were hanging on the walls and pointed out their good points.
"Is carbon paper now used to any extent? »
“Carbon paper is still available, and is still used, but not so much by the commercial photographers, and is probably a little less by the pastoralists because of the introduction of new processes like oil and bromoil ; but many workers have continued to new, and still use it with admirable results”
"Has ' home photography ' had any growth in popularity during the year? »
«Probably the greatest development of photography is in home photography or home-portraiture. During the lat five or six years practically every professional obliged to introduce home portraiture.
"Have there been any notable inventions in photography during the year? »
“I want to make a confession the inventions in photography are not of so much me as the development of the inventions that are still to be perfected.”
“Has the so-called» fuzzy school ' made any converts during the year, or is the tendency to go back to sharp, or sharper, prints? »
“I don’t think there is a tendency to go back to sharp or a sharper print but there has been, or there is getting to be, a better understanding of the loft focus lens."
“Has the pictorial school of photography had any influence on what may be called the chief field of photography, in its larger aspects, at present the moving-picture drama? »
«I feel that probably there pictorial photography has it greatest influence. We furl very 1 few serious film producers who do not study very carefully the construction of their pictures and the lighting of them, together with the proper motion-picture appeal the appeal of the acting They are really looking for all expressions of light and varieties of focus that the pictorial photographer has been interested in.''
"It is said that D. O. Hill, the Scotch artist, who for a while practiced photography with genuinely pictorial results, used paper negatives. Was his success due in any measure to this fact? "
"I don't think it handicapped him and in many instances I feel that it contributed to the simplification of his portraits."
"Do you recommend the use of colour filters in pictorial work? »
“I do”
“Do you recommend fast or slow plates for pictorial work? What about films ' "
"I would prefer to use whenever possible, a slow plate. Films eventually. I believe, will be the only thing used, though not necessarily film packs or roll films."
"Do you mean that the glass plate will be discarded and cut most be used! Is not the fact that most practical (photographers and a great advantage in Ming plates? '
“Of course the advantage of the glass plate is that it is easier to handle out a good thick celluloid film is almost as easy to handle and these films are mainly filed. They are not breakable (and they are being made now in all the various emulsions. Their great advantage is in their lack of weight and their non-halation qualities. A great many photographers use burdened -with plates and the filing and adoring o( them become a .big problem."
“Have any improvements in cameras been made during the year!”
"As I see it cameras have been improved in the direction of the need of the pictorial photographer in that they have longer bellows extension and larger front-boards and are constructed for stability.
As the photographer is working more and more in the open, this is necessary."
“What kind of a camera do you recommend for pictorial works?'
“Personally I feel that every photographer should first learn to photograph with a view camera. As his work develops he finds that it is a matter of getting his inspiration from incidents of life rather than building up his compositions in front of a view camera. Here is where the reflex camera is a great help.''
“Then you recommend the reflex type of camera for serious pictorial work? »
"Yes, I do."
“Would you fit type of camera with a soft-focus lens?”
“Yes, and also with an anastigmatic"
"Have any new lenses been put on the market in 1918? »
“Nose that I know of."
"What do you think of the use of the soft-focus lens generally in pictorial work? »
"I think if pictorial photography were suddenly robbed of the with focus lens it would be a catastrophe."
"Can the same results be secured with the anastigmatic lens by throwing it slightly out of focus?’
"No, for the results obtained with the soft-focus lens are due to its construction."
"What size camera do yon recommend for pictorial work? »
"I think the tendency of the pictorial worker has been to use too large a view camera. It has been demonstrated that size does not determine the artistic value of a picture. I would recommend a camera that is not a burden to the person using it."
"Do you recommend workers to make enlargements from a small sized negative for exhibition purposes? And, if so, what size enlargement do you prefer? "
"I should feel that the work above 11 x 14 is a mistake generally, And that a picture can be just as beautiful and in the long run more beautiful when it is kept within the dimensions of the whole plate ' 6½ x 8½ ins."
“Do you recommend the working up of negatives for pictorial effect?”
“My preference is for photographs that have not been worked up. but if a man in successful in doing this to the extent of losing sight of the manipulation in the compacted picture I see no reason why it should not be done, and I think it has been done with success by some good workers."
“Do you object generally, to manipulation or ' dodging ' of prints or negatives as tending to produce hybrid results?"
"I feel that the practice of doctoring negatives is a bail one, but to achieve a result, if it is well done, it may be justifiable."
"What is the mind approved fashion of mounting prints this year!”
"The most approved fashion is the one that was established many years ago in the presentation of etchings and engravings a white or slightly towel mat sometimes with a ' countersunk centre.' "
“Do you think that an ambitious amateur who desires to do good work can best improve his methods by studying exhibitions, or by studying books on art aim composition? "
“I should say that the by the broke on art and composition are of little value without the exhibitions and that if worked together the book is made more valuable by the exhibition and the exhibition more valuable by the look but the combination is absolutely necessary to achieve result. The tendency very often is that in continued study of books or an exhibition rather satisfies the worker, and he does not devote himself to his own problems of creative work."
"What is the greatest, weakness in the work of the young photographer and how can he best overcome it? "
"I think the greatest weakness of the young worker is the lack of something to express. He is too much interested in the photo- graph for the sake of the photograph alone that is, in the medium or in the taking of the photograph itself. The photograph should is press something."
"Just what do you mean, Mr. White, by 'expressing some thing’? "
"You get down to a very important point. The expression in a photograph may come from what we might call the design of the photograph or the distribution of light and dark to produce a visual sensation, just as a fine rug or piece of lace gives us a satisfaction in design, an expression in design. We can also introduce that into the making of a portrait, and embody not only a representation of the person's features, but create at the same time an interesting design or a better distribution of the parts of a portrait to make it convincing and definite."
"Do you mean that an amateur should go out into the fields with a preconceived idea of finding something to express, of making a pattern or doing something ' original ‘? "
"He should go out into the fields with an open eye and open mind to be moved to an expression of his appreciation of pattern, his appreciation of tone, of values, etc. Let him leave the mind open, and that will tell him what to express. He gets his inspiration from Nature, and he contributes to Nature just so much as he has of knowledge of photography, knowledge of composition, knowledge of tone values he expresses himself that way. I do not believe he should go with a preconceived idea of what he is going to get. He should be moved by his subject. If he is not, he will become blind to the most beautiful aspects of Nature. That is the interesting thing of Nature; the changing light and shadow arc never twice the same. The light is continually changing, and he has combinations and variations that a man with a preconceived idea will miss, and in photography that is the most impressive thing that it can record those subtleties."
"Do you recommend workers to send only new photographs to the exhibitions? In other words, should a worker try to get new subjects continually, or send his older, and perhaps better, work in more limited amount?"
"It would be better to send his older work and keep the new photographs- at home until he has studied them carefully."
"Do you regard photography as giving fair scope to the art impulse in people who have that impulse but are -unable to devote their time to painting, etching, or other graphic art?»
"The question really expresses the idea that photography is supposed to be taken up when they cannot do the other thing, which I feel is a mistake. Photography is an expression, not necessarily as important or vital as the others, but it is an expression, and it can be used along with the others as 'well .as alone."
"In other words, you feel that photography islands on its own merits? »
"I feel that it stands on its own merits absolutely."
"What, in your opinion, is -the distinction between an amateur and a professional photographer? »
"I think the distinction between the amateur and professional photographer is difficult to draw. The greatest distinction that I can see is when the word amateur is applied so that it reveals the love of the amateur for his 'work rather than the sense of the duties involved in it. That is what the amateur gets out of the work; the professional's aim is too often .what the can get out of it in the sale of his products."
"Can the pictorial photographer make a living in America under present conditions, or is the photographer who wishes to make a fair income to be recommended to confine himself to so-called 'com aerial ' or 'professional' work?"
“Being a pictorial photographer does not necessarily prevent this making a living. The pictorial photographer, if he is a good one, is naturally concerned -more in .producing a result than in marketing the result; and as a consequence sometimes he suffers. The pictorial photographer in reality ought to be a financial success, for the tendency is strongly toward the development of the work in that direction."
“Will the ending of the war have a favorable effect on 'the future of pictorial photography and on the pictorial photographers of America? »
"I should say very decidedly yes. It will naturally liberate a great many repressed spirits, and the very liberation will express it self by bringing the worker in closer touch with nature, and the results will show this. I feel that the development after the war is going to be in the direction of art expression. As a specific instance, my own ton, which was sick and tired of photography in general, has manifested greater interest in ft since he has been in the Army in
France, through coming in contact with the old chateaux and the interesting art treasures that are has seen. He has developed a greater respect not only for art, but for photography; and this angle instance has doubtless been repeated in thousands of cases on the part of oar soldiers in France."

Practicus In The Studio: Studio Heating And Ventilation.

        The warming and ventilating of studios is a problem which has to be solved in many ways, these bring dependent upon the construction, aim, and position of the building and the means of the owner, for it is obvious that what will suffice for the small “portable” type of erection inadequate for the large, solidly-built apartment, is which the more fortunate among; us are able to work. There are, nevertheless, certain general principle which must to toasted no matter what to the aim or design and the owner of the little studio should carefully consider what to can but do with the son appropriated to the purpose before parting with it. Among these I would put evenness of temperature, cleanliness freedom from injurious fumes, and economy of fuel, the latter being likely to be more important in the future than it has been in the past.
        The position of the heating apparatus should to carefully chosen, as much depends upon it, and, above all, the error usually made by builders of dwelling houses should to avoided that of placing the stove at the end of the room opposite the door, in which position it create, a draught of cold air and only warms a limited area, giving rise to the complaint that one is frozen on one side and roasted on the other. In warming a studio it is desirable that the store or radiator should to place near the door so that the air is warmed in its passage into the room. In studies which have a glass roof and these are still in the majority - the stove should to placed under the glass, so near to the side light ea possible, as not only to this the coldest side by reason of them being only one thickness of glass as a barrier to the outside temperature, but that the warm air ascending to the roof may rout any snow which may fall upon it I have often known work to be stopped by a thick layer of snow on the glass and in attempting to remove this by mechanical means the glace may be broken, an unpleasant state of things in midwinter.
        With regard to the heating apparatus, there it a wide choice ranging from a boiler and steam or hot water pipes to a portable oil stove, and each has its advantages and drawbacks. On the whole, I have found hot pipes the most satisfactory way of heating, and there if possible, should to run the whole length of the studio close under the side light, a shelf or flat piece of wood should to placed above them, and the front should be screened with wirework (as ornamental as may to), fixed on frames which can to easily removed when the pipes require attention. This screening hides the unsightly appearance of the pipes and does not interfere with the heating; in fact, the top strip or shelf serves to distribute the warm air more evenly. If the pipes are left exposed they must to painted, and it is important that oil paint should to avoid: not only will it emit an abominable odour when it is heated, but it rapidly darkens and becomes unsightly. Although a dark colour is the better radiator of heat, I consider that on the whole paint made of finely-ground aluminium in celluloid, which is sold for die purpose to be the best coating. If any other colour than silver required matching the walls, a useful paint may to make by grinding powder colors of the desired shade in beer, stout for preference. I have not tried Government ale for this or any other purpose, bat I for that its adhesive properties would be too poor. The beer colour is used for painting the funnels of steamers which get rather hotter than the average steam or hot water pipes. It must not be thought- that such an installation is vary costly affair if the existing types as used in greenhouse are selected. They may be had in all sizes, and the makers will estimate for the complete outfit if the cubic contents in the studio in feet are given, with the temperature it is desired to obtain. It is necessary to point out that in severe weather the fire must be kept going night and day, not only that the studio may never lie allowed to become cold, but to prevent the water freezing and causing fracture of the pipes or an explosion of the boiler.
        A useful modification of this system is to have separate radiators, each of which is filled with water heated by an atmospheric gas burner. I know of several studios where they are giving every satisfaction, although a reduction of the gas pressure sometimes lowers the heat to an undesirable extent; to minimize the risk of this the supply pipe should be of ample proportions. A large pipe does not imply a large consumption of gas, but it secures an adequate supply when the pressure is low. When using this or any other system in which gas is burned in the studio, efficient ventilation must be arranged for, or the fumes will cause lassitude and even illness. For small studios one or more of the well-known siphon stoves may be wed with advantage. In these there is a large central Argand burner flanked by two metal pipes which not only serve as radiation but condense the products of combustion into liquid ions. These stoves are economical in use and have a cheerful appearance. Two would probably be sufficient for a 20 by 12 studio. Open gas fires are cheerful looking, but rather costly for continuous use; they have also the disadvantage that unless well fenced in there is danger of clothing and drapery being set on fire, a danger which is also present with open coal fires, and one not to be ignored when children are about.
        Closed stoves for coal, coke, and anthracite are very useful in the studio, but most of them necessitate either a brick chimney or an unsightly stove pipe. Of this group, those burning anthracite are the most desirable, as once started they will burn continuously for months if supplied with fuel. Thus the studio does not get cold during the night, and there is no trouble of fine laying each morning; all that has to be done is to empty the ashpan occasionally. The older type of slow combustion stove known as the " Tortoise " burns coal, coke, or cinders, and may also be kept continuously burning. Although this may seem wasteful it is really not so, for there is no necessity to make up a big fire every morning to warm the place up on a reasonable time, while the wood, paper, and labour required for lighting are saved.
        In certain circumstances oil stoves are the only possible heaters available, and if a good pattern be chosen they are not to be despised. The tall, cylindrical pattern, with a bail handle by which it ran be moved about, are very convenient, and if kept, clean, is fairly free from the odour of the oil. The salamanders, or blue flame stoves, are very effective, but they are mean looking and cannot be shown in a well-appointed studio. I have, however, used one of these in a fancy east-iron tore made for gas, and found it quite satisfactory. I have also found that one of these placed under the darkroom sink rapidly raised the room to summer temperature, the sink itself being warm, while the solutions were easily brought to normal temperature by placing the bottles near the lamp. If it be possible, when fitting hot water pipes, to run a (bend into the darkroom, it is, of course, better in every way than an independent stove.
        From heating the studio to keeping it cool is but a step, and in most people's minds keeping cool and ventilation mean the same thing. This is hardly so, for a studio can be perfectly ventilated and yet kept at a high temperature it may be filled with foul air at a low one. The essential point in ventilation is to have the outlets and inlets for air properly proportioned and placed in such positions that straight-through currents- from one to the other cannot be produced. In single-slant and other studios which approximate to an ordinary room the ventilation can be provided for by opening windows if in convenient positions, or Tobin tubes may be provided as air inlets; as a rule, the inlet should be fairly low and the outlets high. The Tobin tubes, which admit air in such a way that no draught is caused, are of the simplest construction, being, nothing more than long, flat boxes of wood or metal, say, ten inches by three, in section, and about four feet in height. They are placed flat against the wall, and at the bottom have an opening to the outer air equal in. area to their own inside sectional area, with a protective grating. The top, inside the room, is left open, so that the air on entering has a tendency to rise and becomes evenly distributed. Four such tubes are sufficient for a moderate sized studio. The outlets should be of the ordinary grating type, with mica flaps placed high in the walls, so that there is no accumulation of hot air in the roof. For very hot weather a large flap opening should be provided, as high as possible, at both ends of the studio, so as to permit of a free draught from end to end. It is necessary that the coverings should not permit light to enter above the backgrounds, and this can easily be done by fitting inside louvers after the style of a Venetian blind. This is a better arrangement than having a lifting sash or trap-door, as is frequently seen, since the current is more perfect, and there is perfect protection against rain. Of course, there must be a hinged door or shutter inside or outside the louvers. This arrangement is supplementary to the small mica flap ventilators, which are sufficient in cold weather. Small electric fans are very useful for keeping the air in motion in very hot weather, but are not available in many places. The roof of a studio should always be double on the dark side, as this prevents heat from being radiated from the outer roof, which in a north-lighted studio has the full midday sun upon it. In positions where the sun strikes upon the glass it is a good plan to have a long iron pipe, perforated with small holes, running along the entire length of the glass. This is connected with the water supply, so that the glass can be flooded with a gentle stream which quickly evaporates and reduces the inside temperature to a considerable extent. It is also very useful for keeping the glass clean. A flood of cold water is harmful, as if turned suddenly upon hot glass it is liable to make the roof leaky if putty is used for glazing, as it is in the majority of cases.
        Much may be done to give an appearance of coolness by the choice of suitable colors for the wails. Green or greenish grey looks much cooler than red or even buff, while ferns, palms, and other plants assist in producing the same impression. One of the most refreshing arrangements I have seen consisted of a passage opening from one end of the studio fitted as a rockery, with ferns and a trickle of water over the stones. Such surroundings produce a tranquil state of mind in the sitter and tend to the success of the portrait. I have also seen a side window opening on to a dingy mew, turned into a miniature rockery, with a tiny fountain .with goldfish in a lake about two feet across at the bottom. These ideas may not accord with those of the "highbrow" artists of to-day, but they please the average sitter, and that is what we all strive to do.
PRACTICUS.

A Question Of Hygiene.

        The recent epidemic which we have called influenza, because we know of no better name, has robbed the photographic profession of some of its best known members, while others, happily recovered, have suffered severely from it. As it is well known that the disease is most likely to attack those whose vitality has been impaired by any cause, it is worth while considering the conditions under which many photographers work.
        Comparatively few photographic businesses are carried on in premises built for the purpose, and in contriving accommodation for the various branches of work there is often over crowding and poor ventilation, both of which are inimical to health. It is, perhaps, in the dark-room that the worst conditions prevail, and now that bromide paper is so universally employed for printing, a much larger proportion of the working-day is spent therein than was the case when daylight printing was almost exclusively the practice. In excluding white light from an ordinary room there is always a great risk of excluding air as well, and, unfortunately, few dark-rooms are so contrived that when not actually in use they can be thrown open so that light and air are freely admitted. For it must not be forgotten that light has a purifying effect equal to, if not superior to, fresh air. In many cases the door forms the only source of ventilation, and, when closed, the unhappy operator has to breathe the same air over and over again. A good many years ago we were consulted with regard to a dark-room lamp which the purchaser declared was faulty, as, after being lighted for a few minutes, it commenced to smoke and gave practically no light. The dealer from whom it was purchased tested it in his shop and pronounced it to be in good order. This was also the case when we tried it. Finally, we ascertained that the dark-room was only about six feet square, and that it had a well-fitting door, so that "the light that failed" did so through lack of oxygen. If an electric bulb had been used instead of a paraffin lamp the question would not have arisen, but the operator's health would certainly have suffered. We have seen in a prosperous West-End business a dark-room which could only be used by opening the window for a few minutes after developing each set of plates. This allowed a change of air which was quickly used up by the two assistants working there, rendering another stoppage necessary. Here was a waste of time from a business point of view, besides incalculable damage to the health of the unfortunate inmates. It is not always realized that a gas or oil flame, which does much to vitiate the atmosphere of the dark-room, may, with a little ingenuity, be used to create a current for ventilating purposes. Even the electric bulb is of some value in this way, and the small half watts with their much greater heating power should be quite effective. Dampness in the dark-room is another fruitful source of ill-health, and we fear that this condition is often concurrent with bad ventilation, making a truly fatal combination. At least one instance of robust man contracting tuberculosis through working in such a room has recently come under our notice.
        We emphasize the necessity for a sanitary dark-room on account of the much greater proportion of time which is now spent in it. When daylight printing was used for the bulk of the work, perhaps two hours a day was the limit of time for which the operator was actually boxed up; but with bromide nipper as the only medium, he is shut up practically the whole day. Although we have inferred that a printing-out process is healthier for the worker than bromide in a badly ventilated room, it is quite possible to conduct it under adverse conditions, the use of the open arc for printing necessitating much more space and, better ventilation than is generally provided. We have in our mind one work-room where three huge pairs of carbons were being used for printing platinotypes giving off unsupportable fumes, while a large dry- mounting press further poisoned the air. The girl employees looked like candidates for the hospital, and we were not surprised to learn that changes in the staff were frequent.
        The war hag taught us many things, especially with regard to lab our, and nothing has been more clearly demonstrated than that true economy of lab our consists in keeping the worker fit by providing healthy workrooms, working a moderate number of hours, and promoting cheerfulness generally. One bad practice which is common in most small businesses is for the workers to remain indoors during meal times. This should be discouraged, and except in bad weather a little outdoor exercise should be taken. If there is a lassitude and disinclination to do this it may generally be assumed that there is something which requires attention in the state of the premises.
        The more sedentary the occupation the greater the necessity for outdoor recreation and exercise. "Health systems" are too dull for most people and are not likely to be persevered in, but walking, cycling, rowing, swimming, tennis, net-ball, and even football and hockey are all valuable medicines, not unpleasant to take, and the employer will do well for himself as well as for his staff if he practices one or other if possible, and encourages his staff to engage in such recreation.

Assistants' Notes: The Photography of Cats.

        About twenty years ago a photographer living at Ealing came prominently before the public as a photographer of cats; he made them a (penalty, just as the late Mr. Thomas Fall, of Baker Street, had some yean earlier made a name for himself as a photographer of dogs. But sins those charming studies of cats have ceased to come from Ealing no other photographer appears to have made a special study of them. Cats are brought to moat studios, it is true, just as babies are, and a photographer may be asked to visit the home of «pussy," but such events are usually looked upon as being just ordinary, and few operators, if any, give a cat more thought unless it be of the evil variety than they would give to any other subject.
        The picturing of cats appears to attract but little attention. Most of the books about cats are badly illustrated by photography, and to see the beat eat pictures of to-day one must turn to the pages of the Bazaar, Exchange, and Matt, the issue of which journal for the first Friday in every month deals largely with eats, and the illustrations given therein are reproductions of the finest photographs of cats one is likely to meet with. The majority of the studies are remarkably good, bat as the name of the photographer never appears it is impossible for the writer to give praise to the operators to whom they are doe.
        The lighting of a cat needs care to bring out the animal's points, but not so much care as is necessary with a human being. A good light and plenty of it is permissible and, in fact, necessary, because of the brief exposures called for. The most important factor in cat work is the choice of suitable back grounds, and it is in selecting thaw tint the average operator usually cornea to grief. A background cam make or mar a picture of a cat, and I am inclined to write down the hack of rounds of commerce and w need for ordinary sitters as being useless for the work. The most satisfactory plan is to make a series of comparatively small backgrounds of varying colour, using millboard w a base, or, if preferred, light wooden frame, covered with cheap calico or similar material. Such backgrounds may measure about 60 INS, x 40 ins., a trifle larger if convenient but certainly not smaller. The material inboard or fabric is then distempered. If six or eight backgrounds of different shades are made the photographer can (elect the colour that will "how up" the cat to the best advantage.
        An ordinary table is portage the most rentable place or “throne” on which to pace a cat and a background with a continuous place (foreground) which can be placed over the table when the background is get up upon it is an advantage, as it prevents the junction between the background and the table showing in the form of an ugly line across, the plate, though the use of a large lens stop usually eliminates the division to some extent.
        Cats are not so affectionate or as easily managed as dogs, but cats know their friends quite as well as do dogs, though they are not so demonstrative. A cat wandering about a street wills often lake notice of some people, but not others, and in so doing rarely if ever attempts to make friends with the pennon who dislikes cats. And having such mysterious knowledge it is obviously difficult far a photographer who is not a lover of "pussy" to pose one in an artistic or comfortable position.
        The ordinary bulky studio camera is of little we for the work, because of "pussy’s" proclivities for wandering about the table and to the edge of the background. The camera to use with ears and comfort is the reflex, and in the band. Much, however, depends upon the behavior of the feline "sitter." As regards posing the operator most use his discretion awl bring his artistic training into play; souse cats look bait landing up other, lying down the most difficult being a sitting position. Cats, when in a strange studio will stand up or lie down more readily than they will sit. Lastly banish all acrimonies from the picture as many otherwise very fine studies of cats have been cause cats are imitative, and will only comfortable on cushions of their own colour or one very near to it, and when a cat is this pictured it because a disciple matter to brow where the cat ends and the accretion begins. – L. T. W.

EX CATHEDRA: Cheaper Plates; Supplementary Flashlight; Packing Negatives; Field-Camera and Cycle.

Cheaper Plates.

        It is announced that the prices of dry plates have been reduced as from March 11th last. The reduction brings quarter-plates to 3/- per dozen, half-plates to 6/6, and whole-plates to 12 3. Taking the quarter-plate as the basis of comparison it will thus be seen that the reduction to 3/- - from 3/8, which was the figure reached at the last rise on August 1st, 1918, amounts to a fraction over 19 per cent. The present price of the quarter-plate, in comparison with the pro- war figure of 1/3 per dozen, is still 140 per cent, higher. The schedules issued by the
Plate-makers give the complete figures of prices for extra rapid and ordinary plates, panchromatic and X-ray plates in both the English and metric sizes.

Supplementary Flashlight.

        Photographers as a whole are not fully aware of the advantages that flashlight has to offer as a supplementary illuminant when making exposures under difficult conditions. It sometimes happens that a certain amount of day or artificial light is available by which the exposure has to be made that is, in. sufficient of itself to light certain portions of the subject sufficiently for them to be fully exposed before the more brilliantly illuminated parts were hopelessly over-exposed. It is under conditions like these that the flash-lamp, which need only be of a simple form, or which may even be dispensed with if the prepared powder, such as Johnson, is employed, becomes of real assistance in solving the difficulty. We may, in explanation, cite an instance of this which occurred in our own work some years ago. The subject was an interior of an ancient abbey, the building badly lit through stained glass windows, two of which were directly facing the camera. The details of these windows, which were, of course, fairly well illuminated, were required in the negative together with a good rendering of some dark oak choir stalls in the foreground which were very badly illuminated indeed. A plate was exposed by meter for the windows, and just before this period was complete a strong flash was fired, sufficient to illuminate the whole of the interior. Careful development produced a negative that was "just right" for its purpose. The flash should be fired almost at the end of the exposure; if this is done before, there is a tendency for the smoke from the flash to cause a belt over the picture. The above indicates some simple means of overcoming difficulties due to bed illumination, and may be noted by commercial photographers who often are expected to produce first-class results under very unfavorable conditions of lighting. Some may be inclined to adopt the usual reflector and diffuser in connection with the flash, but though this may at times be desirable when dealing with very irregular lightings, we prefer to increase the flash in strength and keep further away from the subject if the building will admit.

Packing Negatives.

        Even in such simple matters as sending a negative through the post there are pitfalls for the unwary of which anyone to whom negatives come is being constantly reminded by the receipt of parcels of glass shattered to atoms by the thump of the post office stamp. Enlarging firms who would caution their customers ought to arrange for them to visit the sorting floors of a big postal depot. It would provide salutary warning against packing negatives between pieces of card or with no greater protection than the cardboard plate box in which they travel at the risk of their lives. Now that so many pursue the photographic process no further than the making of the negative the safe transit of the developed plates to the enlarger is as important an item of after-treatment as intensification, yet many people seem not to know that to make perfectly sure of its safe arrival the negative should travel in a wooden box so that the walls keep the shock of the defacing stamp off it. If it be prevented from shaking about in the box by cotton wool, wood shavings, or even crumpled paper above and below, the sender may challenge the Nasmyths of St. Martin's-le-Grand to do their worst. One other little precaution should be noted. If several negatives of different sizes are being sent together they should be placed so as to prevent the smaller bearing unevenly on the larger. For example, a quarter-plate should not be sandwiched between two half-plates, but be laid upon them with a piece of card between.

Field-Camera and Cycle.

        Those photographers who reside in country districts and have occasionally to carry a heavy field camera and tripod upon a cycle realize that if care is not taken such means of transit are likely to have a very detrimental effect upon their apparatus. The best place for the camera case is without doubt upon a strong back carrier firmly secured to the machine, though some workers have a preference for the front carrier. In the latter position there is a greater tendency for the camera to be shaken about, while if a proper carrier is not used there is a certain strain upon the aides in guiding the machine, especially if the instrument is a heavy one. Even on a back carrier there is a tendency for the case to get badly rubbed, and even the instrument itself may be scratched if a little care is not taken as a preventive. Some time ago, after a cycle journey of some miles across badly made roads, we had the experience of a camera case rubbed right through by the vibration between it and the cycle carrier, together with a broken plate in the dark slide, which necessitated a further journey for the purpose of making another exposure. Since then we have prevented such trouble ever recurring, very simply, in the following manner. A couple of strips of felt about two inches m width and about an inch in thickness, such as may be bought for a few pence at any saddler's, is placed the bottom of the camera case for the instrument itself slides to rest upon, and another strip of felt is I upon the carrier before the case is put on. The felt will absorb some vibration, and the troubles detailed above will not be encountered. We have also adopted this idea when traveling on a motor cycle, when is equally successful. The best place for the tripod is across the handle bars or along the top tube of the cycle. Such a plan is far better than slinging the case upon the operator s back when, if the instrument is a heavy one, its weight is soon felt.

The Future Of Aeroplane Photography

To pass into history – 1917 year.

[The following article, which we reprint from our American contemporary "Aviation," very properly raises the question of the commercial future of photography in the air, in which there are certainly as great possibilities as in aerial navigation generally. The fact that one of the authors, Mr. L. J. R. Hoist, is a camera designer and instructor should emphasize to manufacturers of apparatus the field which is opened by the application of aerial machines to practical methods of surveying.-EDS. "B.J."]

            The commercial future of aeroplane photography is not generally appreciated by aeroplane builders, since they have not as yet realised that preliminary surveying of high-roads, railroad, and other through routes can be done quicker and more cheaply by aeroplane photography than by any other know method. This is largely due to the circumstance that cameras have been hitherto considered as instruments of mere detail in the aeroplane industry as a whole, while as a matter of fact they will probably become one of the most important factors in the development of commercial aviation.
            The most fruitful field of commercial work for the aero plans camera in the United States will undoubtedly be the completion if the topographic survey of this country, which work includes the complete detailing of maps not yet complete, as well as the mapping of territory which till now has not been charted at all. To this already extensive programmer should be added the locating of the high and low water lines along our coasts, besides work of more local interest, such as the production of correct maps of smaller communities for real estate records, the location of sites for dams for irrigation purposes, locating railroads and waterways through mountainous country, establishing aerial routes and emergency landings in vast wooded tracts, etc., all of which work can be done in a fraction of the time, and hence for a fraction of the cost entailed by a complete manual survey.
            It should, however, not be understood that the aeroplane camera renders manual surveying obsolete. On the contrary, it is recognized that the camera does its most, effective work in connection with the slower but extremely accurate work of the surveyor, each one being checked up by the work of the other. In fact, it may be stated that the camera furnishes the fellahin details to a degree of perfection not attainable or, at any not obtained by manual survey whereas the latter produces a series of exact points of location which serve as control points for the data furnished by the camera.
            To obtain useful commercial mapping results from an aero plane requires different methods of operation than those used to make the so-called mosaics, because maps will be made between control points often many miles apart, between which it will be necessary to fill in not only the general ground plan bat also the contour lines.
As a matter of fact, the mapping use of aeroplane photography has been to a certain extent set back by the war, for the reason that certain scientific views, which are not relevant to commercial photography, rather held the foreground. These were questions of emulsions and lens-openings, neither of which is really of as much importance as the purely mechanical sides of the problem.
            Since all work enumerated before it this article is strictly of the order map-making, only such photographic apparatus as is adapted to this class of work need here be noted. This excludes all hand-held or hand-operated cameras as well as any semi-automat or non-automatic instruments which are rigidly attached to the aeroplane, since they partake with it in all its deviations from a perfectly horizontal position while in flight, a condition which is entirely incompatible with results for map-making. This leaves thus the freely suspended camera for further consideration.
            The military use of the aeroplane camera, during the war has led not necessarily form correct precedents, became of the assumption that an observer is essential. This has led to undue emphasis being placed on hand-operated or semi-automatic cameras which were to be of such simplified construction that no imperfect functioning would under the hands of the operator-observed. These military conditions do not prevail, nor apply, in commercial aero plane-mapping.
            A derision of opinion has existed relative to the automatic functions of aero plane cameras among the Allied Governments, but in n case were these difference caused by the requirement of aerial photographer mapping.
            Paramount importance was attached the chemical side of aerial photography much attention being devoted in particular to the perfection of color sensitive emulation to more readily camouflaged objects from the real ones.
            No doubt this aim is worth while but since existing emulsion used with suitable ray filters were apt to produce under the rough and ready condition of actual field photography behind the lines similar if not better remits with a far greater degrees of like hood to get any remits with a far greater degrees of like hood to get any results at all it must be regretted that these efforts placed the much more important mechanical side of the problem entirely in the shadow.
            As long as the question of aero plane photography was a question of filling in maps with nearby control points the detail design of the camera was not of the highest importance. To take a series of views over well-known ground is a problem comparatively simple but commercial application of aero lane photography requires more definite information in regard to drainage, divides and general contour information at otherwise the main benefits of rapid surveying cannot be obtained. Photographic aero plane surveying will unquestionably be used largely as a supplement of the Photo-theologize and other more common methods of surveying, to fill in between control points established by the older methods. But in the case of the more or less unknown country between control points established by the more common methods and for such works a coast surveying arises the greatest need of aeroplane survey.
            Surveying to be done from an aeroplane, particularly for filling in large areas, most is obtained by means of an automatic camera. On considering the problem of commercial aero plane photography it will soon be possible to pick out the necessary elements of design, and why an automatic camera should be used.
            All photographs to be used in map making must be a true horizontal projection of the earth's surface. In this way all points are practically reproduced by the photograph on a scale which is equal to elevation divided by focal length of the lens. If the plane of the photograph is not approximately parallel to the plane of the earth's surface (not considering the curvature of the earth), positions will not be correctly rendered; there is distortion to location which is equal to the cosine of the angle of inclination. In actual military practice, however, any camera installation which fastens the camera to the plane so that in the average flying position the camera is approximately horizontal was considered sufficiently well for purposes of making mosaics.

Contour Mapping.

            However this is by no means an answer to the question of obtaining survey information, as in the case of obtaining contours from aero plane photographs these can only be done by making use of the lens axis of the camera. The only way of establishing a true parallel position of the negative to the assumed plane of the earth is by means of the vertical position of the axis of tin- lens. Moreover, the only known factor for determining contours needed is the angular relation of the axis of the lens and its true focal length. With these two know factors the position of the earth can be graphically reproduced, and by ordinary drawing instruments a series of exposure points in the air can be determined. These exposure points are then used by transference of angles to reproduce graphically the location of points on the ground in space above or below the base line, which is usually taken at the foot of one of the axial points of the series of photographs.
            To obtain a vertical position of the axis of the lens necessitates a free suspension of the camera in the body of an aero piano where it is not affected by the air current in motion. This is easily done by patting the camera in the Gimbals suspension similar to a ship's compass. However, it is necessary to maintain a constant position, as otherwise the variation in the rate of the aero plane through the air would introduce a pendulum action in the camera. There are only two ways whereby this can be done first, the use of a gyroscope, and, secondly, the use of gravity and suitable air cushions to prevent oscillation, but at the same time to allow motion relative to the swinging plane. In practice the latter method is it introduces no mechanical complications and the accuracy resulting is close enough for mapping purposes.
            In to the requirements of angular position, aero plane photographic surveying requires a large number of photographs in a single flight. It is next to impossible to change plate magazines or to fill holders in flight sufficiently rapidly to obtain an unbroken series; moreover, it is necessary that photographs should be taken at what is practically a constant, interval between exposures; if not, there is very apt to be a break between two successive exposures which requires an additional flight to obtain the necessary information with which to fill the gap.
            In a military sense, during the recent war, this matter was not of such importance as it becomes for photographic surveying, for the reason that usually photographs were wanted of a single spot only, and intervening places were not necessary, although at times desirable. This has led to the use of film cameras using roll films having as many as 100 exposures to each loading.
            The principal difference between different makes of cameras for purposes of making military mosaics are usually matters of obtaining necessary power to change plates or film negatives.
            Three methods of obtaining power have been used: the air fan electricity and spring motors.
            In considering the design features of the camera it is very necessary to know to what extent photographic surveying will be carried out. If military mosaics are required, which generally are used simply to fill in small areas, a semiautomatic regardless of form of drive even a hand-operated? Camera -may be useful. If contour surveying is to be done it becomes necessary to have a very accurate timing device for the interval between exposures, as otherwise the overlapping relations between exposures will very easily be lost. The European continent is so thoroughly surveyed that the contour method has been very little used, and in the considerations of the necessary types of cameras, contour mapping has not been considered an essential feature. For this reasons the so-called automatic or semi-automatic camera ordinarily in use is not completely automatic, but simply is a power-driven mechanism which changes a plate or film negative and in which the actual exposure is made either by the or observer. There is only one completely automatic camera in existence which operates at varying rates of speed, controlled with certainty either by the pilot or the observer. This camera the Brock camera will be described later in detail.

The Triple Lens Camera.

            When making flights for map-making purposes a given area of grand can only be fully covered if a number of flights in parallel courses are undertaken, each new flight following a course just overlapping the strip of land covered by the previous flight. The number of flights required to cover a given width of territory will then be directly proportional to the width of the strip embraced by the photographs, and consequently it is desirable to embrace as wide a strip of land as practicable in each view.
            This consideration has led to the construction of triple lens cameras, the central lens pointing straight downward, and the lens on either side placed under an outwardly slanting angle. These three lenses are in one vertical plane at right angles to the direction of flight. The image-planes of the outer negatives are then usually set at an angle of 45 deg. to the central lens. These cameras are arranged for rigid attachment to the aeroplane. The two outer lenses will then produce pictures of strips of land extending far out at each side of the line of flight, whereas the central lens registers the views directly beneath the aeroplane and immediately adjoining regions.
            Although this arrangement undoubtedly covers a width of territory not obtainable with a single lens, it introduces difficulties which seem to far outweigh its possible advantages, and at its best it is only suitable for use on fairly flat ground. The complications arising from (three different planes of projection, and the necessity of afterwards reducing the two outer planes to that of the central one, without definite knowledge of the actual position of either plane at the instant of exposure constantly serious obstacles to the usefulness and commercial adaptation of devices of this kind.

Timing Exposures.

            It seems now preferable to obtain increased width of the strip of land depicted on the photography by increasing its width and reducing the focal length, of the lens, both to such limits as sound photographs and optical practice allow. A camera arranged to take negative. 5 x 7 ins., the 5-in. side in h line of flight and equipped with a lens of 8 ins. equivalent focus, embraces at 5000ft. elevation on each picture a strip of land 4,375ft. Wide and 3.125 ft. long on a scale of 1/7,500, or, if elevated to 6.666 ft., would produce pictures on a scale of 1/10,000 embracing 5,833 ft. in width by 4,166 in length. Most of high-grade lenses at 8-in. focus and openings of /'5 6 will cut a 5 x 7 in. image sharp and without distortion, and are serviceable for such work.
            The succeeding exposures should be timed at intervals of distance depending on the elevation and corresponding length of ground taken by the picture. The speed of the flight translates this distance interval into a corresponding time interval. It is thus desirable to provide means by which the actual time interval can be varied according to these conditions and which will operate with dependable precision in its various adjustments.
            As the manufacturers of the Brock Automatic Camera, it is probable that our actual experimental work in photographic surveying and in the design of cameras to obtain these results has been carried far beyond experimental work in this line by any individuals or by any of the Governments who have participated in the European war. The system of installation which we use has been found to permit exposures of from two to five times the exposure possible with any other system of installation, with all its attendant benefits. No other camera has been successfully built -with a system of free suspension, with the result, also, that no other camera has been built which can also do contour surveying. The importance of contour surveying in a military -sense was becoming recognized as the war drew to a close, and consequently this field of endeavour has had but a fraction of the effort put on it which will be devoted to it in the next few years.
            Another feature of camera design which originated with the Brock camera was the use of film for military purposes. The Brock film camera has been made successfully to use film in two sizes: one 4x5 ins., using ordinarily a 12-in. lens, and one 8 x 10 ins., using a 24-in. lens, both types completely automatic. These cameras were the first ones used which entirely eliminated static electricity in the film, and are to-day the only ones in which static electricity never occurs. The system of obtaining large negatives on film without distortion through the use of a glass support originated with the Brock 8 x 10 in. cameras. However, the use of the large negative sizes will be confined to military purposes, as for commercial or ordinary Government mapping a very large scale is not required.

The Brock Camera.

            Let us now consider some of the mechanical details of the Brock 4x5 in. camera and the reasons for the design. This camera is the outgrowth of a series of experiments to obtain a free suspension camera, motor driven, within reasonable weight, certain of operation, and controlled from a distant point, for use in a single-sealed aeroplane.
            Mechanical experiments led us into the design of the spring motor-driven cameras and resulted in our finding commercially feasible means of controlling the speed of operation of the spring -motor not in any way dependent on friction. The entire engineering profession is aware of the difficulty of obtaining a satisfactory variable speed friction drive which includes both certainty of operation and certainty of speed. In the case of a spring motor this difficulty is emphasized because the control through friction must be done fey the introduction of a governor. Such a construction results in absolute loss of control of speed regulation owing partly Ito the different percentage of friction due to moisture in the air -in varying amounts. The system we use, therefore, is the control of the main spring motor by means of an auxiliary spring motor, which is in effect a clock with a speed regulation of 3*(1/2) to 1. The importance of accurate speed control in the case of the Brock camera is greater than in any other camera, because of its ability to produce contour maps. Wherever it becomes necessary to obtain contours the axial point of the succeeding and the preceding negative must show on each exposure, with the result that exposures must occur at frequent and constant intervals without interruption, other wise a break will partially destroy the value of the contour photographic flight.
            Without any exceptions worth mentioning, all aerial cameras are fitted with focal-plane shutters, as the high efficiency of this type shutter, together with its extremes mechanical simplicity, renders is superior to the between lens shelter. In the Brock cameras focal-plane shutters are prevailed with a fixed slot, the speed adjustment being obtained entirely by means of the spring tension. Spends are variable from 1/50 to 200 of a second or any similar range.

Shutter Speeds.

            Is connection with shutter spends of aero plane cameras it is of particular interest to mention that, owing to the almost absence of vibration obtained, shutter spends can be regulated entirely with regard to the elimination of image movement through traveling spend, and no regard need be paid to the effect of vibration. The requirements due to speed are very easily met. For instance, a camera as already mentioned, fitted with an 8ft lens flying at 5.000 ft. elevation and at 120 m.p.h., reprises no faster exposure than 1 20 of a second to give a sharpness corresponding to a circle of confusion of 14/1000 of an inch and with a speed of 1/50 of a second the circle of confusion will be only 5.6 1000 of an inch. This means that the gumball-suspension has the practical advantage of being able to photograph both earlier and later in the day than would be practical with rigidly suspended cameras, which are generally, used with minimum exposures of 1/100 of a second to eliminate as much as possible the effect of vibration. It also means that such focal-plane shatters can be made with wide slots to reduce the duration to the expense period and thereby the resulting distortion to a perfectly negligible minimum, which in turn eliminates the only meeting valid arguments against focal-plane shutters.

Evenness of Exposure.

            A perfect eventide of exposure at all speeds can easily be obtained by proper design of the focal-plane shutter, in fact so that the slightest difference in exposure plainly seen is aero plane films, since maximum and minimum density adjoin in two negatives of a strip of continuous pictures side by show no observable variation. Especially in the civil or commercial uses of aero plane photography do these various features come to their fullest signification and it is only on this account that they have mentioned in detail.
            Summarizing the status and development of aero plane photographic surveying is an art still in its infancy. Under the aeronautical trade recognizes the possibilities of this use of their product, and unless the engineering profession of the business realize its possibilities it is not likely that the growth will be rapid. It is an unfortunate fact that up to the present time the energy developed to the constructive surveying features of aero plane photography has been sun fined to, and understood by only a few people.
            The truth of the matter is that, in the first place the emission questions which have arisen in Europe are really matters of is serious consequence although a considerable amount of time and effect has been spent to change and to make special emulsion. Efforts have also been made in Europe to make emulsions sensitive to certain colour whereas similar is not better, affects could have been obtained with existing emulsions by the use of a co1our screen and lengthened exposures. Whatever efforts have been made in the mechanical direction they have been very largely in the direction of making a camera which could be operated by the average observer without any knowledge of photography or of mechanics is safe to say that if the motion picture industry which is now in existent had had a military use and military development, the present stage of perfected would never have been leached, as the mechanical side of the motion picture industry has received a tremendous amount of attention for years. High-class motion pictures cannot be made by anyone but a skilled operator, and in exactly the way the success of the future of aeroplane surveying is dependent upon operators learning about the necessary photography and mechanics of aeroplane cameras; but it must be recognized for the future of aero plane surveying that apart from the development of the negative and the printing of the prints aero plane photography is a matter which should be entirely in the hands of civil and mechanical engineers.

Aeroplane Photography and Commerce.

            The modern aeroplane has reached the static of development where the safety of operation and the certainty of operation are as good as of the average automobile of ten years ago. This means that an aeroplane can be used for some hours over entirely unknown country without any landing places: it further means that such country can be completely and correctly mapped without difficulty and at a very low expense compared to the present-day methods of surveying. It is quite possible that in the future preliminary surveys will be made for railroads, roads, and various water-works entirely by aero plane photography and that when the line has been decided upon a party will go out simply for the purpose of staking agreed-upon lines. If the aeroplane industry will devote as much attention to this subject as has been devoted to other commercial possibilities, a rapid growth can be expected. As foundation-stones have been laid, it is only necessary for a general interest in this subject to be awakened by the aero plane industry before possibilities, first as a internment enterprise, and then as a commercial enterprise for civil engineers will find general recognition.