see, by a paragraph in an American journal, that Mr. Carey Lea has lately, like myself, been dissolving the image on bromised plates by the too liberal use of ammonia. Sooner or later, when some hundreds of operators have repeated this mortifying experiment, that detestable, pernicious, and dangerous substance, ammonia, will be banished altogether from the dark room. It would almost seem as if photographers had always had a perverse tendency towards the employment of such chemicals in their art as are unwholesome and disagreeable to themselves, and dangerous to everything they touch, whilst simple and comparatively harmless substances would have answered their purpose just as well. Ammonia nitrate, ammonia fuming, ammonia in the hypo bath, ammonia for doctoring the nitrate bath, ammonia in the developer, are all quite unnecessary. I am convinced that ammonia and the carbonate may, with advantage, be banished altogether from the photographer's shelf. Its fumes are very unwholesome to inhale, and they do an infinity of harm to other chemicals in the dark Another suggestion which I would offer to the Liverpool Company is to modify their organic preservative in such a way as not to give such very red negatives. This redness produced by tannin has always a tendency to yield excess of density in the blacks, and to destroy harmony and softness in the picture. Tannin negatives are proverbially hard. The blacks must be most carefully watched, or they go to an extreme. I cannot say how this excessive redness of the Liverpool plates is to be modified, because the process by which they are prepared is a secret in its minor details, but I do certainly think that it may be reduced with advantage. room. Let me now sum up. Six plates, prepared ten months ago by the collodio-bromide process, and exposed during that time to extremes of temperature varying from 20° to 100°, as well as to extreme conditions of atmospheric dryness and moisture, and to sea air in a steamer and a yacht, have proved as good and as faultless in all respects as anyone could expect dry plates to be if freshly prepared by any process. Their sensibility remained very nearly, if not quite, equal to that of good wet collodion plates, and the three of them which were properly developed yielded as good negatives as one would desire to see, having sufficient printing density for the usual process, and that obtained without the use of silver for developing. This is surely a grand result; and I most earnestly hope that this fine process will receive all the attention it deserves, both from practical and experimental operators, this summer. Those who merely wish to take pictures on a tour, with the least possible expense and trouble to themselves, I advise by all means to use these plates, and procure them ready prepared; and to experimental photographers I say, give up for a time all other researches, and devote your energy to the collodiobromide process, for in this new mode of preparing a sensitive film lies the germ of an immense development of photography, both professional and amateur. Afterwards, when this process has been mastered, try the substitution of collodio-chloride for collodio-bromide of silver. May the time soon arrive when the nitrate bath shall have become a thing of the past. slide during the course of years, I have observed a blur upon this screened margin, wherever the sky has been bounded by it. This blur is, however, not present in any of the negatives taken upon the Liverpool plates, which were painted on the back with annotta. Other parts of the negatives show also the same freedom from blurring. The paint at the back is therefore a good thing, which ought not to be omitted. The cause of blurring is this:-The sensitive collodion film is semi-transparent or translucent, like a piece of tissue paper or ground glass, and it becomes illuminated by the Everyone image which is cast upon it by the lens. knows that a substitute for a broken ground glass may be made by exciting an iodised collodion film upon a clean glass plate, and also that the image upon such a film can be seen in all directions. It follows, therefore, inevitably, that this illuminated film, from every bright point of which rays of light proceed in all directions within the glass plate upon which it lies, must give reflections from the back of the glass upwards, towards the back of the film, and that this must produce blurring. The mode of preventing injury to the negative from these reflected rays is to cause them to assume a non-actinic colour; and this is done by painting the back of the plate with orange-coloured paint. Rays reflected from the back of the plate will then take the colour of the pigment, a fact which can be very easily proved by experiment, and such rays will of course be chemically harmless. Mr. Carey Lea has lately suggested to colour the nitrate bath by the addition of reddened litmus, so that all the chemical rays may be absorbed by the film, and only the be transmitted. This appears to me non-actinic to be a sound and valuable suggestion. rays FULMINATING SILVER. A CONTRIBUTOR to Humphrey's Journal says:-"Fulminating Some years since I was suddenly awakened about midnight by a loud explosion; on rushing into an adjoining apartment I found that a quantity of iodide of nitrogen, which had been reposing quietly for some weeks at the bottom of a small glass jar or bottle, covered with water, had suddenly vacated its previous quarters and taken up a position on the ceiling overhead, where it covered a space of ten or twelve feet, more or less. An incessant series of small but deafening explosions, seeming to testify to both rage and satisfaction, occurred as fast as the porous plaster absorbed the moisture; the room was filled with dense vapours of iodine, so as to render it almost impossible to breathe or even see. Fortunately I had a quantity of hyposulphite at hand, which was soon in a basin of water, a towel saturated and applied, soon brought the enemy to terms, before any more serious consequences ensued. Many other compounds of nitrogen are similarly or even more dangerous-the chloride and the compound with gold, for instance-and had better be avoided. On this account I prepared a different salt, which answered the purpose nearly as well, although collodion containing it would not keep so long as the other. The mode of operation, as nearly And now a word or two about blurring. The Liverpool as I recollect, was as follows:-Into about two drachms of the plates are painted yellow on the back, and the paint has to strongest aqua ammonia, I dropped carefully small crystals of nitrate of silver until the liquid became muddy; then a few be wiped off with a wet rag before developing. On comparing the dry-plate negatives thus treated, with three wet grains of nitrate of ammonia, or a drop or two of nitric acid, was added until it became clear again; nitrate of silver was then collodion negatives of the same subject, taken on the same occasion, and also with a dry-plate negative not painted, I dropped in again, until the liquid was saturated at a temperature of about 180 or 200 degs.; about an ounce of alcohol was observe a marked difference in the former, which I will then added, and heated rapidly to the boiling-point; during endeavour to point out. The frame of my stereoscopic slide which time the clear solution should pass through various shades covers about three-eighths of an inch of margin at of brown and red, until finally nearly black; on cooling, a each end of the plate, upon which, of course, no light light floculent black deposit should subside, leaving the soluNevertheless, in tion colourless, and of sufficient strength to crystallise in a solid can impinge directly from the front. mass below 60 deg. all well-exposed negatives that I have taken in that I have still another box of plates received from the Liverpool Company along with those the treatment of which I have just described, and I hope in a few days to expose them, and report results. Pencil Jottings. POSING. BY R. A. SEYMOUR. S the tastes and opinions of different people are so commonly varied and antagonistic, and attempts to please everybody always end in pleasing nobody, I have made it my policy to alternately please and displease everybody. I find that I have succeeded. Before me are two letters, private, on the subject of these Jottings. "A." says, "You offend me sorely by giving such commonplace posings from photographs when you might sketch us selections from the works of great painters." "B." says, "Stick to the photographs; posings from paintings are all very well for painters, but they are, as a rule, of but little use in the glass-room, partly because they require more time and study than the photographer can afford to give them, and partly because commonplace people think the more simple the pose, so that it is easy and natural, the more likely it is to please their own taste, and that of their friends." I confess that there is some truth in both these letters, but I shall nevertheless go my own wilful way, sometimes selecting from paintings, &c., and sometimes from photographs. The above pencil jottings are from three excellent photographs by Mr. Parry, of Newcastle. I am pleased to find that, in expressing the opinion I have of this gentleman's artistic ability, I only echoed a verdict editorially pronounced in a large number of London and provincial newspapers, including photographic contemporaries. If a Chloride of silver dissolved in just sufficient ammonia to make a clear solution, is stated, by a correspondent of the Chemical News, to be a very delicate test for free acid. little of the test is added to ordinary spring water, the carbonic acid present in the latter will neutralise the ammonia and precipitate the chloride. Mr. Evans has presented to the New York Institute of Engineers a photograph of the high level tunnel of the Central Pacific railroad. The east end of the tunnel being sometimes illuminated at sunrise, a large mirror was employed to reflect the sun's rays equally over the whole of the interior, while the picture was being photographed. The plate having been exposed about fifteen minutes, a print was taken showing every detail, even to the timbering of the drifted headings, with great distinctness and accuracy.-Scientific American. THE AMATEUR PHOTOGRAPHER. BY A. H. WALL. IT would be interesting to trace the varied motives which different persons have in becoming photographers. Some take it up from their love of science, some from a passion for chemical experiments, some as an art, some as a pastime, and some as a business. And according to the spirit in which the art is pursued, so do its productions vary both in character and in merit. The scientific photographer cares not for picturesque qualities, or for perfect technical results; his sole aim is to discover some fresh fact, or develop some new theory. The chemist-photographer seeks perfect chemical conditions, considers his work done when these are attained, and thinks a few roofs and chimney-pots taken from a London housetop as good a subject as any other. The artist photographer strives to produce a picture displaying greater or lesser æsthetic aspirings, according to the degree or kind of taste, sentiment, or feeling for art which he possesses. The photographer practising the art merely for amusement, seldom attains any very high standard of perfection in his productions, because he is unwilling to throw into it the requisite earnestness and effort; and the photographer who regards his art simply as a business; seeking only to please his customers, produces bad work in a low neighbourhood, decent work in a decent neighbourhood, and a better class of work when his customers are refined and educated. So long as his patrons are satisfied he is contented, and however bad his work may be, he makes no effort to improve it so long as it sells. His productions may be those miserable abortions commonly displayed in such popular London thoroughfares as Whitechapel or the New-road, a libel on his art, and degrading to himself, as showing how, although devoid of the ordinary good qualities essential to the making of a decent bricklayer or costermonger, a man may yet pass muster as a photographer; yet he is satisfied, because, as he is always ready to tell you, "Oh, they're good enough for my customers." Such photographers, be their work good or bad, have no pride in their work, no interest in the progress of their art, and, worse to say, they are always ready to sneer at those who, more noble and generous in their natures, love the art they practise, and take delight in its elevation and improvement. Highest amongst all those who practise photography is the earnest, enthusiastic, hard-working amateur. With pure, disinterested affection, he is ever striving to improve in his art. He is a constant reader of all the photographic journals, and would be were they twice as numerous and double their present cost. He is a member of one or more societies, and attends the meetings regularly. Photographic editors know him, not only as a seeker for information, but as a valuable and useful contributor, always ready and eager to help where he can, and to aid or please his photographic brethren in any possible way. His work takes rank with the best and the highest. Where is the professional photographer who can produce better photographs than our amateurs show? Look through the folio of the Amateur Photographic Association, and tell me if, in the works of the same number of professional photographers, pick them from where you may, you can get together a collection surpassing them in the same admirable qualities? And the reason is plain-is all summed up in the simple reason-Love. It is "the labour we delight in " that brings the greatest success, and there is high warranty for the fact in the perfection of a universe which owes its being to God's Divine love for His creatures. The Mastrat, one of Theodore's wives, seems to have been of an heroic turn. After the fall of her lord and master, she, unlike the rest of his wives, boldly threw aside her royal robe of crimson enriched with gold, and coming from her tent into the presence of the soldiers-if her majesty will pardon the expression-like a man, had her photograph taken. She looked every inch a queen, and one who could lead an army. Photographic Wanderings.* THE RHINE. BY G. H. THERE are few things more enjoyable than a voyage on the Rhine, and we are surprised that, while many of our best photographers have doubtless treated themselves to this luxury-not necessarily a very costly one, by-the-byeso few have brought us home really good photographs of its varied and picturesque scenery. We must perforce confess that the best photographs we have seen do no more than scant justice to its Hills, all rich with blossomed trees, There is so much of antiquarian interest, so much of romance, historical and legendary, attached to this beautiful locality, that we should imagine photographs which did justice to its charms would, if published, be sure to command remembering the awful deeds enacted within their gloomily defiant walls, we find in their present silence and desolation a source of grim satisfaction, which only their picturesque beauty can change into admiration. So much by way of hint. On some future opportunity I may pursue this theme in an account of an autumn ramble by the Rhine. PASTE FOR MOUNTING PHOTOGRAPHS. "A PRACTICAL MAN," writing to a contemporary on adhesive mediums for mounting photographs, says, "The general fault in paste-making is in not having it sufficiently smooth and sufficiently boiled-not burnt. Pastes may be made of dextrine, rice, starch, or flour. Paste made with flour was extensively used by the old water-colour painters-Turner, Girtin, Varley, Walmsley, and others. If paste were guilty of all that is sometimes laid to its charge by photographers, it could scarcely fail to injure the tints of many of the delicate water-colours used by these masters in producing their charming effects. Yet their drawings have suffered no further change than that of receiving the 'golden tinge of age,' a very different thing from the sickly yellow tone of a fading photograph." [But it must also be a ready and extensive sale. Scenes, sombre and solemn, or majestic and grand, or gay and lively, abound upon its banks, affording rare and rich opportunities for a display of artistic taste and feeling on the part of an artist photographer. The numerous remains of old castles abounding on the Rhine have over and over again been engraved and written about. Dating from as early as the seventh or eighth centuries, their histories read like a series of wild, spirit-stirring romances. Intended at first for protection against the incursions of barbarous enemies, they gradually became the strongholds of savage and unscrupulous robbers, who were the terror and scourge of the unfortunate people such castles were at first intended to protect. Seeing where "all lonely and wild stand these roofless abodes," and G. H. confesses that he has not seen Mr. England's series, from one of which our graphotype illustration is drawn.-ED. †The conclusion of E. R.'s paper, "An Afternoon at Burnham Beeches," has not reached us, in consequence of the author's absence from England on urgent business. remembered that the essentials of preservation are not the same.] To keep paste from becoming mouldy, "A practical Man" adds, "you should put in a few shreds of isinglass and a little essential oil of cloves. A good serviceable paste is made by first preparing a basin or cup full of strong starch, according to quantity wanted, to be made with hot water poured from the spout of a tea-kettle with the steam well up. When the starch-paste has become cold, put it into a wash-hand basin or pan, and rub well up with the hands-in fact, wash the hands in it; then return the same to the cup or basin, and put on one side to ripen. This will be known to have taken place when the paste loses its blue tinge, and becomes white. It will now be found as thick and smooth as butter, and can be spread over paper with the finger, so as to form a clean and even film. This paste may be mixed with prepared gum-one part gum to two of paste. The gum should be dissolved in clean soft water, and then strained through flannel for use. A very useful and available article to keep paste, &c., in, is one of the common mustard-pots that have covers fitted to them for keeping out dust and dirt. It is as well not to leave the brush in the paste, but to well wash it after using, and put by for another time." PRACTICAL DETAILS OF THE DRY BROMIDE white of egg to each ounce of water; keep it in a tall, PROCESS. (Continued from page 187.) BY MAJOR RUSSELL * AFTER being excited, the plates should be washed in three or four changes of distilled water, which may be used for a great length of time. Keep the water in tall, large-mouthed bottles, with paper covers to protect it from dust, each bottle holding more water than is required for use, that it may be poured off free from deposit of bromide of silver. Number the bottles to ensure their contents being always used in the same order. Do not leave the plates long at rest in the first washing water.† When this has acquired much nitrate of silver by long use, precipitate the silver from part of it in the form of carbonate, wash the precipitate in the way which has already been described (see note, p. 187), and put it into the bath evaporating dish. Then fill up the first bottle from the second, and so on, filling the last with fresh distilled water. After each plate has been washed by moving about for about a minute in each of the distilled waters, put it into common water to soak for some hours. Perhaps the most convenient way is to put the plates in a rack made on Mr. Thomas's plan; a box with a handle coming above the surface of the water, open at both ends, with grooves bevelled so that the films cannot be touched. For washing in plain water, the rack may be made of wood, and well coated with varnish or solid paraffin. If a wash of weak albumen is used, it should be after the soluble bromide is washed out, for the albumen makes the collodion less permeable and retards the washing. However the albumen be kept undiluted, when diluted for use it should be acid to test paper. Either hydrochloric or acetic acid will answer well; the former is probably the better.§ The albumen wash may contain five minims of If the motion of a plate is stopped while being dipped in the first washing water, as in the exciting bath, the film will be marked by the surface of the water where it stops. It is a good rule to plunge the plates for the first time into every fresh liquid, without stopping. The backs of the films hold unconverted bromide, which washes out gradually; in a weak solution of nitrate of silver this soluble bromide is converted in the liquid outside the film, and unless the plate or the water is frequently moved, a slight deposit of loose bromide of silver will remain on the surface of the collodion, which will then look rather dull when dry. A cloud of minutely divided bromide of silver will remain suspended in the second and third washing waters, but will do no harm. An examination into the state of these waters after long use is very instructive; remarks on this subject would occupy too much space here, but may be given at some future time. The length of washing necessary to give full sensitiveness depends mainly on the physical nature of the collodion films. By the method now recommended, as will presently appear, little or no soluble bromide need be left in the films. This is an important simplification; the more the plates are washed, the more sensitive will they be, and it is scarcely possible to wash too much. If washing for an hour is nearly enough for full sensitiveness, plates so treated will show but little difference in quality from others, similarly treated otherwise, but washed for three days. It is desirable, however, always to wash plates prepared with the same collodion for about the same time, because, if much soluble bromide is left on one plate, and scarcely any on another, they will not only differ in sensitiveness, but will require different development. It will probably be found best, on the whole, to leave the plates in water at this stage, well protected from light, for some convenient interval, as twelve or twenty-four hours. § Very dilute albumen is not easily preserved; carbolic acid in it seems to form some combination which destroys its efficacy. Acetic acid will preserve the albumen for a time; essence of lemons answers well, except that undissolved excess of it floats on water, and must be removed by filtration. Hydrochloric acid has only recently been tried; one drop of strong, fuming acid to each oz. of water, and five minims of albumen, were found to work well in every way, and the liquid has kept perfectly good for many weeks through the late hot weather. This quantity of acid, however, is large, and unless well washed out again would be likely to impair sensitiveness. Hydrochloric acid is an excellent solvent of albumen, and would probably keep undiluted albumen well, if in sufficient quantity to make it acid to test paper; this has not yet been tried. In the instance just mentioned, the albumen was very old, and contained wide-mouthed bottle, well-corked. The liquid should be filtered when first mixed; afterwards, like the washing waters, it may be poured off sufficiently free from deposit. When the plates have been washed in common water, put them into the albumen bath for five minutes, then wash well again for a few minutes in several changes of common water. Alkalies and carbonate of lime were long ago found to have a bad effect with tannin. Common water usually holds carbonate of lime in solution by means of carbonic acid. When the water holds much of the chalk, some of it is likely, in spite of rinsing the films afterwards with distilled water, to remain in them when the tannin is applied. The carbonic acid evaporates as the film dries, and the chalk acts on the tannin. To prevent all risk of this, it is a good plan, whether albumen has been used or not, to mix one drop of pure glacial acetic acid, or two drops of the weak kind of formic acid, with each ounce of the distilled water with which the films are rinsed, and of the tannin solution. After washing the plates, put them on a pneumatic holder, and rinse by pouring on a little of the slightly acidified water, waving it about equally all over, and pouring away. Repeat this two or three times, and then apply the tannin. If the tannin is to be washed off, it may be from 10 grs. to 40 grs. to the ounce; if to be dried on, 5 grs. to 10 grs. to the ounce will be strong enough; in the latter case it should be constantly filtered to remove dust, and should be kept on the film long enough to penetrate well-say five minutes at least. If the tannin is washed off with common water, this should contain a trace of a volatile acid, finishing with a little distilled water, also slightly acidified. In all dry processes with which I am acquainted, it seems to be the best plan to let the plates dry spontaneously, the more slowly, in reason, the better. Draining plates so as to make perfect films is not so simple a thing as might be supposed. It is difficult to make the liquid always leave the lowest corners freely enough; the consequence is a comparatively insensitive patch at that corner, if any trace of a soluble salt is left in the film. Again, dust for half an inch or more from the lowest corner, and reis apt, by a curious action, to rise up floating on the liquid maining on the film, the specks of dust make insensitive spots of some size if the liquid contains soluble salt. After trying a great many methods, the following has been found by far the best:-Bore holes nearly inch in diameter, along the bottom of the draining stand, at a convenient distance from the upright board; moisten the upright and bottom boards well with a wet sponge, taking care that the insides of the holes are well moistened, and pass the sponge along the outside of the bottom. Cut into essence of lemons and carbolic acid, but smelt very slightly of the latter. When diluted about one hundred times with water, the addition of hydrochloric acid seemed to release the carbolic acid from combination, for the liquid smelt much more strongly of it. The alkalinity of albumen, especially if it contains ammonia, makes slightly washed plates more sensitive, and inclines well-washed ones to fog; but experience shows, now that the subject is better understood, that it is a bad plan to leave much soluble bromide in the film, and to counteract its evil effects by an alkali. Dry processes have been published which would in this way give great sensitiveness, but were very uncertain; for it was difficult to get the proper balance. Something of this faulty plan was accidentally embodied in the bromide and tannin process. It is a much better and simpler plan to secure sensitiveness by washing out the unconverted bromide thoroughly, and to prevent fogging by keeping the films free from alkaline matter up to the time of development; when this is done, the bromide of silver has little tendency to fog. In some recent trials, a little acetic acid mixed with the tannin seemed to cause a decided improvement in sensitiveness and facility of development when the tannin was washed off again; when it was dried on, no difference could be detected, whether the acid was used or not. Formic acid seemed to have a slight advantage over acetic acid, possibly because the latter was adulterated with sulphurous or sulphuric acid. To obtain the highest sensitivenes, the acid mixed with the tannin should be of a kind which will entirely evaporate away as the collodion dries spontaneously. Citric acid, one part to one hundred of tannin, caused a barely perceptible loss of sensitiveness, but otherwise the plates prepared with it worked well. lengths of about 4 inches some cotton-wick of the kind used for spirit-lamps, moisten the cotton by alternately wetting with a stream of water, and squeezing with the hand; if always treated in this way before being used, the same cotton will last indefinitely. Double the cotton and pull through the holes from below with a piece of wire, about inch of which at the end is bent to a right angle, nop until the doubled part stands about inch above the surface of the board, and press it down with the finger so as to make a little hillock. The draining stand is to be propped at both ends so that the cotton hangs vertically in the air below. Set the lowest corners of the plates on the cotton; the plates will stand firmly and drain freely, quite free from dust; if set up over night, they will be dry by morning. The stand should be in a cool place, free from draughts, for the more regularly the films dry, the safer will they be from those curious drying marks to which all dry plates seem to be liable when subject to sudden changes in the rate of drying. The backs of all dry plates should always be painted. Any non-actinic colour will answer, transparent colours being the most effective as a rule. Burnt sienna does very well; it can be bought, roughly ground with water, for about 2s. per pound; mix with a considerable proportion of gum or dextrine (the latter should be boiled), and treacle enough to keep the paint when dried as soft as will well bear handling. Keep the paint of proper consistency in a wide-mouthed bottle, well corked, with some carbolic acid to prevent mould. Use with a flat camels'-hair brush, the handle of which should be made cylindrical to fit tightly a hole in the cork, so that the brush may always be kept soft in the moist air in the bottle. The backs of the plates may be painted as soon as the films are nearly surface dry, but not dry enough to look transparent anywhere. The plates, as soon as painted, should be set up again on the damp stand; the paint being outwards, will dry sooner than the films. When the plates are not wanted in a hurry, and the stand is in a place quite safe from light, it will be better not to disturb the plates at all until the films are dry, and to paint them afterwards. TRESIZE'S DEVELOPING TENT. MR. J. Q. A. Tresize, of Zanesville, Ohio, U.S., sends us a description and drawings of his developing tent, which we give below. He says, in the beginning, that it is not a dark tent, but is well illuminated by yellow light. It is composed, as the cut shows, of four posts, 5 ft. 10 in. in height, and 1 in. square, and six braces, of 5 ft. 9 in. long, and 1 x in. thick. The braces are riveted or bolted together in the centre in pairs, and are all fastened to the feet of the posts by strap hinges, and to the top of the posts by pieces of iron about in. thick, with a T on the upper end, the iron being fastened to the brace; and the T slides up and down in a groove that is cut through a piece of heavy hoop-iron, which is fastened to the top of each post, a corresponding groove being cut into the post about in. deep, to admit the sliding of the T. The irons on the posts are 11 in. long, and the grooves through them 10 in. long; and there is a spring catch at the lower end of each to hold the T down when the tent is open. From top to top of the two front posts is a cross-bar 1 in. square, halved at the ends, with an iron strap round each end, to come down about in. on the posts; and from one end of this to one of the back posts is a bar, with pins near each end, which drop into holes in the front bar and the top of the back post. It is then supplied with a frame on which to place the chemical box, as seen at A A. The frame is all hinged together, and drops into the notches of the braces, except at each back post, where is a pin in the end of that piece of the frame that enters a hole through the post, as seen at A, in the cut. This frame and these bars left off, the tent folds up into the space of 4 in. square and 6 ft. long; and, including bars, frame, and camera-stand legs, weighs eleven pounds. It may be of half the weight and be abundantly strong. When open it is 3 ft. square, and may be covered with cloth, seamed all up except in front. I use muslin painted with chrome yellow. The cover will add about nine pounds to the weight, and remains on the frame all the time. Then I have a box made of thin poplar measurement. The top has 3 in. of the front attached to it, boards, 3 ft. 1 in. long, 10 in. high, and 8 in. wide, all outside and raises up and is hooked to one of the braces of the tent, while the lower 6 in. of the front falls down, forming a shelf 14 in. broad, and the top furnishes a shelf 3 in. breadth. This box or case is set upon the frame in the tent, and when shut can be carried by the handle attached to the lid. Into this I pack my camera, top of stand, chemicals, bath, and tin cistern (which holds one gallon and a half of water), two vulcanite trays, and a gutta percha sink (with elastic pipe) lead off the waste water, each in a compartment to itself. The cistern This case all is set up on movable wire legs when in use. filled, with plates in box, and everything for three dozen stereo negatives, weighs twenty-eight pounds and a half. I have carried it in one hand and the tent in the other, one mile; and I can set it up in four minutes, and put a plate in the bath, and can pack up in four more. Fig1. To make this more plain, we reproduce from Mr. Tresize's drawings cuts of different sections of the apparatus. In fig. 1, d is the Fig Fig 3. post; a a, the grooves in the hoopiron strips: b, the T sliding in the grooves and attached to the top end grooves of the brace c; g is the catch to hold the T of the brace down. Fig. 2 is the bottom of the post and brace e, with a strap-hinge, f, connecting them. Fig. 3 is a section of the braces e c crossing each other, and bolted together to open and shut, and a T at the upper end of one. Fig Fig 5. Fig. 4 is a top view of the frame marked A, in the full set resting in the crossings of the braces, and on which the chemical sticks are held together; and iii notches, to rest in the crossbox is placed. hhh are hinges, by means of which these four ings of the braces. p p are the heavy wire pins to go into the posts. Fig. 5 is an end view of the chemical box open, made and used as described above. The whole arrangement is very simple and complete, though the description of it makes it seem intricate and complicated. Philadelphia Photographer. Heplies and Discussions. ENLARGEMENTS ON CANVAS. SIR,-I find you have an extract on enlargement on canvas, copied from the Philadelphia Photographer, in yours of last week, and I may say I am somewhat interested in that kind of work. I found also in one of your contemporaries of the 25th January, 1867, an article as near as possible the same. I write to inform you I have tried both, and failed. First, there is nothing to cause the silver to adhere to the canvas; next, the soda softens the colour of the canvas, and comes away like milk, being anything of a picture with it. The reason is quite apparent to anyone at all acquainted with the action of soda on paint. Mr. Pouncy has done something in the enlarging by his carbon process, but requiring transposition, I think this objectionable, also extra troublesome. I may say I wrote to the editor of your contemporary after having failed and sought further information. He promised an article on the subject, but it has not yet appeared. I think the canvas must be prepared by some other way unlike painter's canvas, to give good results by the solar camera, for which it alone is valuable. If an article of the kind were brought into the market, with a good working receipt, given to the consumers of so many yards, it would command a ready sale with good profit, and be a great advantage to those at a distance from professional enlargers. Hoping to hear of the experience of some of your readers on this subject.-I am &c., |