the latent picture with finely-powdered fluor spar, or, gives what he calls its "Echoes" in the pages of a photograrather, with fine kryolith powder (3 Na Fl, Al2 F13), phic contemporary, edited by G. Wharton Simpson, instead of enamel colour; next cover it with thin plain said "echoes" being, some one said, like the famous Irish collodion, and apply dilute sulphuric acid. The fluor spar ech es, which answer how do ye do with pretty well I thank powder adheres only to the parts protected from the light, you. The author must, it seems, go about with a noteand on these the etching extends also. When the half-book, always ready to report any chance conversation he tones contain less light than the shadows, these take a pro- may happen to overhear, and hence, perhaps, he was portionably less quantity of fluor spar powder, as the enabled to give us, last week, the following, apparently lights in this manner become correspondingly less deeply verbatim, report of a conversation about the General Relief etched." Fund for Photographers : M. Becquerel has recently published a work called La Lumière les Causes et ses Effets, in which, speaking of the principle of Mr. Bing's actinometer and others, he says:To secure such a method giving comparable results, it is essential that the photographic paper should always be prepared in exactly the same manner, and have nearly always the same hygroscopic condition. Without such precautions it would vary in sensitiveness. But, admitting the paper to be always in the same physical condition, it will be understood, especially when ordinary papers prepared with chloride, bromide, or iodide of silver are used, that we can only have indications more or less upon the chemical action of light, and no determination of comparative intensities. Again: if the most refrangible portion of the spectrum acts with nearly equal intensity under the same circumstances, the least refrangible portion acts, on the contrary, more intensely as the compound has been influenced by light." The Rev. J.B. Reade, F.R.S., writing to a contemporary, the British, points out, with respect to coffee, as used in the photographic process it names, that ammonia exists quasi-ammonia in the raw bean, although it is more abundant in the roasted bean, and "given off in still larger quantities from the red ash of a burnt bean after the flame ceases. As the ammonia escapes from the ash it is received, in ipso motus initio, on the drop of hydrochloric acid spread over the glass slide, and crystallised by evaporation." Paraffin has often been proposed as a substitute for wax in coating photographs. A contemporary-the News-says it will not prove satisfactory, and for the following reasons:-"It is, in the first place, a difficult thing to make and keep an encaustic paste of paraffin, from its singular tendency to crystallise out of its solvents, whether the proportion added have been sufficient to form a paste or a solution. If a solution containing fifty grains (say) of paraffin in an ounce of benzol be prepared at a temperature of 70° Fahr.. it is probable that if the temperature fall to 60°, much of the paraffin will be found to have crystallised out of the solution. If a thick paste be prepared by shredding the paraffin fine, melting it, and then adding sufficient benzol to make the consistency required, it is probable that in a few days the solvent will be found to have partially separated, and the paraffin will show a tendency to crystallise. When this paste is applied to the albumenised print-especially if the weather be coldinstead of assuming that soft, unctuous quality which characterises wax, and which finally yields, on continued rubbing, a hard, polished surface, it behaves quite differently. When the solvent has evaporated, the paraffin begins to assume the form of dry scales, which rub off the print instead of adhering to its surface, so that it is difficult to obtain more than a very slight coating of the material on the surface of the print, and therefore impossible to secure the same depth and richness which can be obtained with a paste of which wax is the chief constituent." Having corrected the above in slips, I feel called upon, as an unpleasant duty, to add one more to my little budget of paragraphs. There is one who calls himself, in print, "An Old Photographer," who, in private, is said, by authorities, to be Mr. Robinson, and who, every month, "It was a fatal mistake," remarked one photographer, "that the first appeal to the benevolence of photographers should have been made for an individual instead of a general cause. If the same effort had been put forth for the relief of all the needy and deserving in the photographic community, it is likely enough that a very large sum would have been secured at once, which, augmented by annual subscriptions, might, if carefully administered, have met with some efficiency all cases of need for years to come. Unfortunately it was not so, and the trouble which those having charge of the Goddard Fund seem to have had with the recipient himself and with his executors, and the attempts to cast discredit on their conduct by men of no credit, will probably check many in any effort to establish a general fund." "The expenditure of so much effort for an individual fund was clearly a mistake," rejoined another; " but it is easy to be wise after the event. But the aim was a good one, and the troubles in the way could not have been anticipated. As for the attempt to malign those who did the work in the Goddard business, I should hope that no men of sense would be deterred from doing a good thing because of the snarling of two or three pariah curs." After some further conversation, another gentleman remarked:-"The real difficulty is a common one; what is required is a beginning. Many will be willing to work and give when once the thing is begun, if the project be begun under satisfactory auspices. If a committee of a dozen trustworthy men were formed, with an active secretary, or two secretaries, also men of standing and reputation in the profession, I feel satisfied the project would soon become a success. Find the men willing to take the first steps, and all required steps will soon follow in due course.' Now, in reference to the first of these real or imaginary photographers, the appeal for Mr. Goddard was not the first made to the benevolence of photographers. In the next place, unfortunately, great and repeated efforts have been made for the general cause without effect. In the third place, if the exposure of the conduct of the trustees of the Goddard Fund checks those who would manage a much larger charitable fund in any similar way, I am happy to hear it, for in that case it has done real practical good to the community. The second speaker-I hope, for the credit of photographers, he is imaginary-generously regrets that so much effort should have been made to relieve one who, to quote from the original appeal made for Mr. Goddard, "found the art at a dead-lock, and gave it an impetus it has never lost;" "who helped the art when it much needed it," and who was "a photographic discoverer and a worthy man" in the very deepest state of distress and destitution. But let this generous fellow console himself by remembering that, so far from the Testimonial Fund doing the hapless Goddard any good service, it only plunged him into greater distress, and rendered his previous miserable position even more bitterly and unbearably miserable. Therefore, my very good, generous-hearted, excellent photographer, if you really exist out of Mr. Robinson's fancy, go and picture to your amiable self the misery and torture of poor Goddard's last days; chuckle and rub your exulting hands to know that, if it was clearly a mistake to make such an effort for such a purpose, at least that purpose was never carried out by your much-admired and belauded friends the trustees. The "Old Photographer" winds up the dialogue by adding:-"I must confess that I am much disposed to agree with the last-quoted speaker. Who will begin? Perhaps none is so fit as the long-established editor of a long established journal. Will our editor, the first projector of such a scheme, undertake the duty, and at once invite subscriptions ?" [Nothing is more common than mistakes as to causes of To this the long-established editor wisely and prudently failure. We have known such attributed to the best of lenses, replies in a footnote:-"We scarcely agree with" An Old to the purest of chemicals, and to most valuable formulæ. WithPhotographer" here. A journalist has rarely sufficient out doubting the honesty or apparent earnestness of our correleisure to permit him to undertake such duties and respon-situated than to a badly-constructed room. Many years ago we spondent, we certainly think his letter points rather to a badlysibilities. Our sympathy and aid may always be calculated built and worked in just such a room as that Mr. Sutton on in such a matter; but we have long made it a rule not recommends, and with good success during the summer; but it to accept the charge of moneys in any such case. Besides, also proved a failure as the winter came on, and so would any the first step is organisation, in the course of which a other glass room have proved in the same position, for, with the treasurer will necessarily be appointed. If necessary, we change of season, direct light altogether deserted the place, and will at all times aid in transmitting money to such an only the feeblest of diffused reflected light remained. The officer, but we cannot undertake his office." I am glad blunder was our own, and it was a stupid one. We feel sure to hear it. Vale. that the principle Mr. Sutton advocates is the correct one, and we know that some of our most experienced and successful operators have for many years past worked in rooms constructed on this principle. Whether it is the best for a bad situation or not, is, however, another question, open to discussion.-ED.] Keplies and Discussions. TO THE EDITOR OF THE ILLUSTRATED PHOTOGRAPHER. SIR,-In last week's ILLUSTRATED PHOTOGRAPHER, under the "To make the matter clear to those of our readers who are not familiar with the processes involved in the operation of fixing a silver print by hyposulphite of soda, we may briefly and simply re-state the nature of the reactions:-On the first contact of the chloride of silver in the prints with hyposulphite of soda, a double decomposition takes place, producing hyposulphite of silver and chloride of sodium. Hyposulphite of silver combines with an excess of hyposulphite of soda, and forms a double salt freely soluble in water. It is on the presence of this double salt that perfect fixation depends, because there is a second form of hyposulphite of silver which is produced when there is not an excess of hyposulphite of soda, and which is comparatively insoluble in water, but soluble in a strong fresh solution of hyposulphite of soda This sparingly soluble hyposulphite of silver is formed when the fixing solution is nearly exhausted, or when the solution from any cause is prevented from acting freely on the print; and it is to the presence of this salt, and its subsequent decomposition, that the yellow stains of imperfect fixation, either as small spots or universal mottling, are due." Shades of Davy, Priestley, and other pioneers of chemical science! where did this editor receive his chemical education? To analyse his assertions and prove most of them to be erroneous would be superfluous. But perhaps this very learned man has, after all, made a discovery, and found out that there are two kinds of hyposulphite of silver. The "Photographic Society" would, no doubt, believe him were he to assert his claims before the council, and give him a medal too, as it did once before for another new discovery.-I am, &c., PORTRAIT STUDIOS. PH. D. SIR,-Pray allow me to entreat photographers, through your columns, to have nothing to do with the portrait studio recommended so strongly by Mr. Sutton in your last. I was unfortunate enough, some years ago, to be attracted by a glowing description by Mr. Sutton of a studio he had designed somewhat similar to this, and made one according to his directions. The result was ruin; for a time at least I succeeded in getting pictures on favourable days in the spring and summer, but was then much troubled with the sun; for, place this sort of studio how you will, the sun will be troublesome on one side or other. In the winter I was compelled to shut up because I could not get my customers to sit long enough, and my neighbour got all my business from me. I had ventured my all on this studio, which I expected would be a great success, and lost my money. After a few years' struggle I am successful again, and have forgiven Mr. Sutton; but I think he should be careful ROYAL CORNWALL POLYTECHNIC INSTITUTION. SIR,-I enclose you herewith two extracts from the Western Morning News, which had a reporter on the spot; the first appeared on Thursday, and the second on Friday: "ROYAL CORNWALL POLYTECHNIC.-Yesterday's attendance at the Royal Cornwall Polytechnic exhibition was slack, although the weather was by no means, everything considered, of an unfavourable character." "ROYAL CORNWALL POLYTECHNIC INSTITUTION.-Yesterday did not present much, if any, improvement in the attendance at the Polytechnic exhibition; and in that respect there is now no doubt that this year's meeting is not of the most satisfactory character." Also, extract from the General Advertiser for West Cornwall, of Saturday : "ROYAL CORNWALL POLYTECHNIC.-The exhibition has not been so largely attended as in former years, although there were many special and important attractions." These are all correct, and in strict accordance with the facts. Compare them with the statements made in your contemporary, the News. Honesty seems a scarce quality in some quarters.-I am, &c. Questions and Suggestions. B. W. A PHOTOGRAPHERS' BENEVOLENT SOCIETY. SIB,-The cry for a provident or benevolent fund for distressed photographers has once more been raised in one of your contemporaries. All very good, if it could be carried out honestly; most praiseworthy too, if one had faith in those who propose and advocate the scheme, and in the honesty of those who, it is also proposed, should carry it out. I fear if the person recommended to "undertake the duty, and at once invite subscriptions," were to make the attempt, he would find the purse-strings of the benevolent very tightly drawn. He was one of the most prominent of those who collected subscriptions for poor and distressed Goddard, to the amount of some hundreds of pounds. Yet, while all this money was in hand, Goddard was languishing in an almshouse, and finally left to die the death of a pauper in a common hospital. Before any attempt is made to get up another benevolent scheme, it will be necessary to see first what has become of this money, for very little of it ever reached afflicted Goddard. Depend on it, sir, this matter must be closely seen to, and the money properly accounted for, before it will be possible to carry out any undertaking of the same kind, at least with the same men at the head of it. I am astonished that anyone of that Goddard "unaccountable" committee should moot such a B. L. There are narrow-minded bigots who cannot distinguish between a dispute and a quarrel. They are commonly coarse, vulgar, conceited fellows, who consider abusing the only way of convincing an opponent, and are always prone to substitute insults for argument. The writer you mention appears to belong to this class; he will probably receive wholesome castigation from the quarter you name. We are as much amused, as you must have been astonished, to find the purpose of your letter to a contemporary so singularly misrepresented in the "Answers to Correspondents." PHILO. You had better keep your very acid crystals of nitrate of silver for printing; they will do very well for that purpose. Use recrystallised and neutral nitrate for your negative bath, and acidulate if necessary. (2) If your stale albumen. We would recommend you to reject it altogether, as prints obtained on it will most probably have less permanence. project, or allow it to be mooted, in the columns of his journal, albumenised paper smells so badly, it is evident that it has been prepared with until he had washed his hands clean from the stain which still sticks to them.-Yours, &c., POCKET APPARATUS. A SUBSCRIBER. SIR,-Having read with considerable interest Mr. Sutton's articles on " Landscape Photography," and believing that if the system were faithfully tried, it would considerably increase the number of photographic amateurs, I am anxious that any obstacle to this success should be at once removed. I believe such an obstacle to exist in the difficulty of obtaining separate parts of the outfit necessary. If Mr. Sutton insists that we must adopt his method in every respect, then it is evident that comparatively few will care to invest four or five pounds in an outfit for this special class of small picture. I do not think this is really his meaning, but it is clearly the meaning of the manufacturers. For instance, I have a small 44-focus Ross's lens, that would do admirably for these small negatives; but when I inquire the price of a small camera alone, the price asked is more than the catalogue price of a mahogany bellows stereo camera. To such a demand I will not submit; so that unless I can find a manufacturer who will be content with a reasonable profit, I must be content to go on in the "old way.' Amateurs already possess expensive outfits, and are not likely to reinvest for articles many of which they already possess. A strong but cheap outfit would be hailed as a boon, and would sell accordingly.—I remain, yours, &c., MR. RAINE'S CAMERA. H. C. SIR,-In your last, Mr. Sutton recommends an arrangement for vignetting the pictures in a panoramic camera. I have succeeded by merely making the centre partition more on a pivot at the bottom of the camera, formed by a wire going through the centre partition, and continued through the top; to this is riveted a piece of watchspring, fastened to a stud; this, on receiving a slight touch with the finger, vibrates backwards and forwards quite long enough for the exposure of a wet-collodion plate, and effectually vignettes the one picture into the other.Yours, &c., THOS. GULLIVER. OUR SEPARATE MONTHLY ILLUSTRATION. IT having been represented to the proprietors of THE ILLUSTRATED PHOTOGRAPHER, by various persons, that the separate monthly illustration is not generally appreciated by its readers, they propose devoting its cost to the literary department of the journal. We trust this alteration in our original programme will be approved by the majority of our subscribers. To Correspondents. Mr. Beattie's appeal in behalf of the unfortunate widow of the late Mr. Pearson has, at present, resulted in the receipt of the following sums ;H. Parkes, Belfast, 10s.; "A Consumptive Father," 1s.; A very poor Photographer, 61.; A Printer, 2s. Gd.; A Man out of Work, Is.: W. H. Kennedy, 1s.; A Little Boy, 6d. ; G. H. D., 25: A Clerk, Gd.; J. B., 2s. 6d. RECEIVED." Marlow's antidote to optical halation;" J. R. S;' ." "Old Pupil;" Diogenes (in our next). JOHN SYMONS.-Mr. Dawson says he cannot instruct you in Mr. Edwards's method of carbon printing without Mr. Edwards's permission. The whole affair is, as yet, a secret among a few, and the inventor himself only has the power to divulge it to others. PHOTO-MANIAC.-Mr. Wilson has not retired from business. You can obtain all his best and newest photographic efforts by writing to him at Crownstreet, Aberdeen. We are not aware that he has any agent in London or elsewhere. S. D.-You are a little too cunning. See our number of June 19th. (2) Apply for permission to visit a plate-glass factory to Mr. Gosslett, Soliosquare. He may or may not give you leave, according to circumstances. LIONEL LORIMOR.-Liquids are not allowed to be sent by post; send it by the Parcels Delivery Company. AN IRISHMAN.-(1) Glauber salt is simply another name for the sulphate of soda. (2) The instrument is called a Goniometer, and its use in crystallography is to determine the angles of crystalline substances. QUERIES.-O. G. Rejlander, 129, Malden-road, London, N.W. (2) We co not know where you can purchase old plain collodion; try some of the firms that advertise collodion; probably you may find one who has got an old stock. E. B. P.-Thanks for your kindness. We shall be very glad to receive an account of your trip for publication, and to illustrate it from your photographs. Be good enough to excuse our mistake; recent experience has taught us to be cautious in such matters. BELMONT-You should have enclosed a piece of one of the negatives which showed the stains instead of prints. The stains seem all to be of the same character, and most probably arise from the collodion, since you say you have changed your nitrate baths without avail. Change your colledion for that of another maker, and then report-progress, we hope; or better, send us a piece of one of the negatives, when we can, in all probability, tell you the cause of failure, and how to avoid it. Have you seen the suggestion Mr. Rejlander offered you in our issue of September 25th. ABERDONIENSIS.-You are quite at liberty to practise your carbon process without obtaining a license from Mr. Swan, or anyone else. We shall be glad to see some specimens from the carbon tissue prepared by yourself. You need be un er no apprehension as to legal penalties being enforced. Of this we can assure you from the opinion of a very eminent Q.C. ENAMELLING PAPER PRINTS.-In giving a formulæ for this purpose, on page 414, we gave the name of Lavery instead of Savery. W. H. R.-It is evident that our contemporary, the News, is fast increasing in unpopularity with its readers. Here is another letter which has just reached us from one of its oldest subscribers, pointing out instances of unscientific reasoning and bare-faced, vulgar self-laudation. We really cannot insert it. W. H. R. will see that this number, and several other recent numbers, have contained remarks smiliar to his own, and we fear lest we should appear ill-natured and spiteful if we inserted everything on this subject which crops up so continually in letters from correspondents. V. B. laments the non-existence of a provident relief fund, and yet thinks the insertion of such an appeal as that made by Mr. Beattie on behalf of the helpless widow and her innocent little children (see page 412) should not be allowed. He might as reasonably argue that because a workhouse cannot hold all the houseless wretches who apply at its doors, it should be done away with altogether. We, however, so far agree with V. B. as to regret the necessity there is of parading an upfortunate man or woman's private cares and troubles before the public, as the only available means of procuring them the assistance they urgently require, and may well deserve; and we moreover believe, that every such case, so long as a general provident fund remains unknown, reflects deep disgrace upon photographers as a class; but so long as they deserve such a reproach, so long we, at least, shall seize every opportunity of reminding them of it. The conclusion of Mr. Fennessy's "Purposes of Science," and a number of other papers are crowded out. The weather is still in a very unsettled state, a not very remarkable fact when reference is made to last week's report. Barometrical pressure has been very fluctuating, the atmosphere highly charged with moisture, and the wind continually "backing." However, the wind, since yesterday morning, has veered from S.S.W. through W. to W.N.W.; there is also a slight decrease in the humidity. Should the wind continue in the present quarter, and barometrical pressure increase, dry and fine weather may be expected, with a 'decrease in the temperature, more especially at nights. LONDON, OCT. 16th, 1868. DESTRUCTIVE TESTS ON CARBON PRINTS. N consequence of Dr. Taylor's unfavourable report of the effects of moisture on a few of the specimens of carbon prints that were submitted to him for examination, I have thought it right to repeat the experiments recorded at page 405. On the present occasion the carbon prints or photographs in pigment were of the same kind as those which I had previously tested, namely, three printed by the Auto type Company, three by Mr. Edwards's new process, and three by Mr. Woodbury's photo-relief process. None of them received a second fixing by me in alum. I took them as I found them, and, therefore, just as they would be when sent out to the public. After soaking for ten days in cold water, they all remained absolutely unchanged, not one of them exhibiting the slightest symptom of leaving the paper to which they were attached. It may be as well to mention that the temperature of the water during the whole time of immersion ranged between 55° and 64° Fahr. When I performed my previous series of experiments, the temperature of the water was higher. To that fact I attribute the speedier destruction of the prints on that occasion, as most of the prints, on which I was now operating, were clippings from the pictures previously tested. Finding all the prints unaltered after ten days' immersion, and finding also that, by friction with the finger the pigment could only be rubbed off with difficulty, I raised the temperature of the water to 85°, at or near which it was kept for twelve hours. At the end of this time the pictures were still unchanged, but now the pigment could be rubbed off with great ease. The temperature was again raised to 160°, at which they all, save one, partially or entirely left the paper, either in shreds or in fine particles, in times varying from thirty minutes to two hours. The exception I have referred to was a clipping from a print sent me by Mr. Edwards, specially for this trial. I do not know how it was printed or transferred; certainly it was not printed by any of the silver methods. It had to be boiled for fifteen minutes before I could discern any trace of alteration. At last it burst out into minute blisters, and in a few minutes afterwards left its mount altogether in small fragments. Another set of experiments on cuttings from the same prints has been going on in one of my rooms for now over a month. Instead of immersing these pieces in water, I placed them, picture side upwards, on a folio of several folds of blotting-paper; and, in order to keep them flat and in contact with the blotting paper, so as also to let them have free access to air, I placed over them a piece of very open wire gauze, which was pressed down at the ends. The blotting-paper has been kept saturated with water by means of two capillary twists of cotton immersed in waterjars. In this condition the prints have been lying for more than a month, and they still remain unchanged, either by the action of the moisture from below, of the air from above, or of both combined. no method of answering it summarily. But of this I feel assured, if danger is really to be apprehended from that quarter, it is the only one that threatens the destruction of such carbon prints as those which I have recently examined. POUNCY'S CARBON PRINTS. In a postscript to a letter published in THE ILLUSTRATED PHOTOGRAPHER a fortnight ago (see p. 423), I acknowledged the receipt of several of Mr. Pouncy's pictures, which he had destined for "torture." Three of these were on prepared painters' canvas, and three on paper; and were all excellent reproductions in different-coloured pigments, from not very fine negatives. One of those on canvas has been handed to Mr. Wall, for an experiment in painting upon such media. His report thereon will be duly published. Cuttings from the others have undergone considerable "torture," with the following results. Steeped in cold water for six days; no alteration perceptible. While they were still moist, friction with the finger would not disturb the pigment without destroying the paper; and no amount of hard rubbing affected the prints on canvas. By the way, it may be interesting to your "Gossiping Photographer" to know that the clipping from the canvas print, after it had been in the water for a few minutes, rolled itself up as tight as a pencil-case, and so remained while in the water. I was not in the least "suspicious,' on that account, of the stability of Pouncy's picture. But to try whether this curling up might not be in consequence of any peculiarity in the preparation, I cut a piece from one of Roberson's prepared canvas for painters, and placed it in the water with the rest. As I expected, it curled up quite as tight as the other. Seeing that cold water had not the least bad effect on Pouncy's pictures, I placed the paper ones in water at a temperature just under the boiling-point, and kept up that temperature for six hours. After that treatment no change in them was perceptible. Lastly, to make this severe test complete, I boiled the piece of canvas picture, which had already been in soak during six days in cold water, for six hours. No change was thereby apparent, except that the whites of the picture became somewhat dingy, and a dead instead of a glossy character was given to the image. But the same deadening and dimming of the surface was also apparent in a piece of Roberson's prepared canvas, boiled along with it. I may briefly say the water test, hot or cold, had no destructive effect whatever on Mr. Pouncy's pictures. I then tried another test, founded on suspicions recently promulgated. It has been asserted by some, that because asphaltum, which is Mr. Pouncy's sensitive medium, fails in the hands of painters, it must necessarily also fail in his process. Asphaltum, or bitumen of Judæa, the objectors say, runs or melts by heat, and therefore should not be used. That may be all true enough, when bitumen is applied with the brush to a painting; but there is really no similarity between the two processes, if what is stated about paintings be true. For instance, I hung up in a gas oven, three slices from Pouncy's pictures, two being on paper and the other on canvas; and I purposely selected for the experiment those portions of the pictures which presumably should contain the greatest amount of bitumen. In this oven they hung for six days in a temperature ranging from 300° to 400° Fahr. On matching the cuttings with the prints from which they were severed, no change whatever could be discovered. From all these experiments, I am now fully convinced of the truth of an opinion which I have already strongly expressed, to wit, that photo-carbon prints, when properly manipulated, are practically indestructible by their greatest foe, moisture. To test them with those substances which destroy silver prints is altogether unnecessary. We know they must, from their very nature, be proof against such destructive agencies. But there still remains another test of stability, which I cannot see my way clearly to apply very readily. Might not vicissitudes of temperature, combined with the action of air, induce these pictures, after a lengthened period, to crack or crumble from their mounts? THE ILLUSTRATED PHOTOGRAPHIC ALMANAC is in Time alone can answer that question satisfactorily. I know preparation. See advertisement columns. VOL. I.-No. 37. Before I made this last experiment, I anticipated the result, from knowing something of the chemical nature of the compounds used in producing the image; but I confess I was hardly prepared to expect these transferred pictures to bear hard boiling without suffering some very apparent injury. PATENTS AND INVENTIONS. BY THOMAS SUTTON, B.A. THERE was an amusing and caustic article by " Nitric Acid," in the number of this journal for July 31st, headed "To Thomas Sutton, vid THE ILLUSTRATED PHOTOGRAPHER," which I ought to have answered long ago; but better late than never. The writer seems to object to Patents, and argues that they do no good. Many other writers are of the same opinion, and they tell us what is not strictly true, viz., that most of the really great discoveries and inventions in photography have been generously given to the public. Having myself taken out three patents at different times for inventions, I feel a personal interest in this question, and a little hurt when one is reproached, by implication, for want of generosity. Now, in point of fact, what great photographic inventions or discoveries have been generously given to the public? Daguerre received a pension for life from the French Government for his discovery; and he then patented it in England, and sold the patent. Fox Talbot took out a patent and granted licences for his process. Poitevin, Pouncy, Pretsch, Swan, and Woodbury have all taken out patents. What grand discovery has not been patented? The collodion process, the reader will reply at once. True; but the use of collodion instead of paper, in Talbot's process, was suggested by Bingham, who had tried it, and published the result of his experiments long before Archer published his celebrated letter in the Chemist. But Bingham used gallic acid and dry plates, whilst Archer used pyrogallic acid and wet plates. True again; but be it remembered that Archer and Bingham were intimate friends, and experimented together at that time; so at least the latter gentleman told me the other day; and they had both worked upon wet plates with pyrogallic developer at the time when Archer wrote to the Chemist. Neither of them could have claimed a patent, and neither of them foresaw at the time the great value of that process. Be it remembered also, that Archer afterwards patented a camera which bore his name, by which act he departed, I suppose, from the generous policy which he may be supposed to have followed on the former occasion. If his instincts were so generous in one act, why were they not equally generous in the other? But is there nothing on the other side of the picture? No one great and original process that has been freely given to the public? I am afraid not. Mr. Mungo Ponton freely published some experiments which he had made with bichromate of potash; but it is quite certain that he did not foresee the value which could be made of them, or he would surely have prosecuted them further. Now, let us look at the optical part of the business. Whether Petzval patented his original portrait lens I cannot say, but I believe he patented his orthoscopic lens, and tried to prevent Voigtlander from making it. There was an angry discussion carried on between them at the time, in my Notes, which the reader can refer to. The panoramic lens was an original curiosity, and I am sorry to say I patented it. Other patents have been obtained for lenses which I will say a word or two about presently: The stereoscope was not a patented invention, but what is its true history? The principle was discovered by Wheatstone, and correctly explained by him. He used both reflectors and lenses, and employed geometrical diagrams to illustrate a scientific curiosity. Photography was also discovered about that time, and Sir David Brewster perceived the adaptation of the new art to the instrument. He suggested the use of half-lenses to displace the images; and to take the pair of photographs from stations never exceeding 24 inches apart, even when the moon was intended to be viewed in relief! The dis placement of the images by half-lenses has since been abandoned, and the moon has been taken successfully from stations equivalent to thousands of miles apart. The whole theory of the stereoscope, as laid down by Brewster, has been shown to be wrong, and as laid down by Wheatstone, to be right. But in all this I perceive the science, though not the generosity. Brewster could not have patented the lenticular stereoscope, because it was not his invention; while Wheatstone clearly could not foresee the great commercial value of his invention when developed by the aid of photography, and he treated it as men of science are accustomed to treat a scientific curiosity-that is to say, he got the "kudos" which attaches to a thing of that kind when in the form, as it were, of a latent image. So much for the great and leading inventions in photography, viz., the Daguerreotype, Talbotype, and Collodion processes; Carbon Printing; and the Stereoscope. Let us now turn to some minor ones, in which patents have not been, taken out, and which have been freely given to the public. What has happened? Why, that modifications, not always good, of the original invention have been quickly patented by some modifier, to suit his own selfish ends. Take the case of the triplet lens, an invention given to the public by the writer of these lines, and for some modification of which a certain optician took out two patents. Take the case also of the deep meniscus lens, which was patented by the same maker six months after its properties of flattening the field had been publicly explained by the same writer. Take the case also of the doublet lens, invented by Thomas Ross, and of which a modified form was subsequently patented by the maker before referred to. What, then, is the use of giving an invention to the public, if a patent is to be subsequently granted to some selfish person who may choose to introduce a sens less modification of it, and use his patent as a means of advertis ing, and gulling the credulous? Is it not just as well that an inventor should take out a patent himself? "No," some one may say, "let the gullible be gulled; the indiscriminate granting of patents brings money to the exchequer." Clearly, then, I think, we must not talk any more about the generous policy, or of the generosity with which great inventions have been given to the public. The true policy should, I think, be this: if a man should stumble upon one of those little steps by which we are all enabled to mount a little higher in our processes and appliances, let him by all means publish the fact in return for what others have done for him. But if he should make a really grand discovery, the full value of which he can foresee, and should devote time, and brains, and money to working it out to something like perfection, then by all means let him patent it, if by doing so he can benefit himself. No one will be really injured by his patent, except such selfish beings as I have alluded to in the former paragraph. REDUCTION OF SOLUTIONS OF THE SESQUISALTS OF IRON TO PROTOSALTS BY NASCENT HYDROGEN. BY W. J. LAND. WHILE engaged in the analysis of nitrates by M. Pelouse's method, I find that solutions of persalts of iron are perfectly reduced to protosalts by nascent hydrogen. As I do not remember to have seen a record of such reduction of ferric salts (in solution), I am induced to offer this, hoping that something of iron-salts, or to the restoration of developers, &c. The followuseful may result from it, either by its application in analysis ing will serve as an example of the experiment, which may be modified in various ways:-If to a solution of persulphate of iron, a small quantity of sulphuric acid and iron filings are added, an elimination of hydrogen will take place, but the greater part of the gas at the moment of liberation unites with the oxygen of the persalt, and in a short time reduces it to protosulphate, in which no trace of a higher iron-salt can be found. The experiment is best made in a flask with a small neck, loosely stoppered; and, if the solution is to be tested for persalt, the flask should be fitted with a valve opening outwards. The temperature should be raised, that the perfect expulsion of quickly peroxidise some of the reduced salt. I have experithe atmosphere may be effected, the oxygen of which would mented upon the mineral acid salts of iron. The organic acid salts would probably undergo like reduction with the proper material for generating hydrogen in their solutions.-Philadelphia Photographer. |