THE GREAT SOLAR ECLIPSE.

THE Mechanics' Magazine, in the course of an article on photographing the great eclipse, says :-" Although the photographic results of the expedition are not so successful as were desired, some valuable experience has been gained. Photography in the tropics is very different to photography in England, so much so that manufacturers of photographic goods make special apparatus and chemicals for use beneath an Indian sun. Collodion of inferior quality rapidly be comes useless by exposure to tropical temperatures, and for use in those regions collodion is commonly made with a larger proportion of alcohol and a minimum quantity of ether, because of the rapid evaporation in coating plates. The difficulties of photography in the tropics are further augmented by the liability of insects and dust to get into the apparatus, and to settle upon the prepared plates. Morcover, the heat tends to dry up the silver solution upon the plate, and to produce black spots in development. "In future, this last evil, which has so much troubled Major Tennant, can be altogether abolished in tropical photography. The operations of exciting and developing a plate are essentially distinct; in fact, there is no necessity whatever to keep such a very strong solution as 30 or 35 grains of nitrate of silver to the ounce upon the plate during exposure and development. Two baths can be used in future, the one containing nitrate of silver of the ordinary strength for the excitation of the plate, and the other a 10 or 12-grain solution only. The excitation of the plate can be nearly completed in the first bath, and then it should be immersed for about a minute in the second. Then, when the plate is placed in the dark slide, it will be covered with a solution one-third weaker than that on the plates exposed by Major Tennant; consequently, the salt will be much longer in crystallising upon the film, so as to produce spots. Development goes on much better, especially in hot weather, when the plate is covered with silver solution of considerably less than half the ordinary strength.

"But a still further step can be taken towards the preservation of the plate in good condition under tropical temperatures. Glycerine may be added to the weak second bath just recommended, and then the plate will keep in good condition for hours, without crystallisation of the nitrate of silver. At least, in the hottest English summer weather, such plates will keep for five or six hours, and a whole day in winter. All the other manipulations will be exactly the same as in the wet process. Probably, when a simply iodised collodion is used, without bromide, the plates will not keep so long as five or six hours, for such collodion will stand less rough treatment than bromoiodised. Rapid dry plates, with all their troubles and uncertainties, are at present out of the question in astronomical photography, but there is no reason why the glycerine process, which differs so little from the ordinary wet method, should not be adopted. Practical experience with the glycerine process has shown that the addition of a little organic matter to the glycerine bath improves the photographic quality of the resulting negative, honey dissolved in water and filtered being preferably used for the purpose."

In New York the directors of the Park Bank, in establishing regulations for their new safe-deposit vaults, have adopted the idea of identifying each lessee of a safe by his carte-de-visite.

Speaking of the annual exhibition of paintings in Milan, a correspondent says in the Athenæum "The slashing criticism on the exhibition by a highly artistic friend is, It will be kind to say nothing about it, as there is really nothing fit to be seen in the whole collection.' The best of the Milanese painters are not, however, represented. "I have some photographs,' continues my friend, that certainly taken from far better things than anything in this exhibition; although from a photograph one cannot judge the colour.' This is interesting as evidence of the value of photographic reproductions of paintings.

seen

are

The Exchange Club.

A new four-guinea achromatic microscope, by Field, of Birmingham, for a Ross's stereographic doublet, a good half-plate lens, or a copying camera up to 8 by 63; also a 21-inch achromatic telescope, for a carte-de-visite rolling press.-Address, T. H., Fir-tree Cottage, Southgate, N. I have a lens for condensing, a solar camera, and apparatus for the magnesium light, which I shall be glad to exchange for a good sewing-machine.-E. G., care of the Editor.

I can exchange a Clarke's magneto-electric machine for a Photographie lens.-J. Moody, 43, Junction-road, Holloway. I have a 4-plate photographic camera and lens, portable dirk room and chemicals, which I should be glad to exchange for a good electric battery, or a small printing press.-C. Baker, Arthur Cottage, Arthur-road, Kingston-upon-Thames.

a

Thos. Forrest, Market-street, Pontypridd, wants to exchange first-class-plate portrait lens, by Lerebour, with Waterhouse and front stops, for either of the following lenses:-Ross or Dallmeyer's stereo, small carte, doublet, or rectilinear. J. Tibbett, High-street, Dunstable, will exchange a 38-in. telescope and a violin for carte-de-visite apparatus.

For a good velocipede I would exchange a 4-plate lens and camera, sliding back, two baths, two printing frames, and a quantity of glasses, chemicals, brushes, and paints, &c.—T. Westworth, printer, St. Helen's, Lancashire.

I have a 1-plate apparatus, by Ross, some chemicals, and albumenised paper, which I will exchange for a foot lathe of equal value.-E. Hall, 42, Upper Spencer-street, Oldham.

J. S. Martin, photographer, Dufftown, has an excellent 12 by 10 landscape lens and camera, folding tail, rising fronts, and extra groove for dark slide; also a good whole-plate portrait lens, by Francis, London. He is in want of a No. 2 Dallmeyer's portrait lens, of the ordinary rapidity, 8 inches focal length, or almost any other description of photo goods.

I have a camera-stand, pictorial background, two slips, and a head-rest, which I wish to exchange for a stereoscopic camera and lenses.-J. Duncalf, 27, Claughton-road, Birkenhead.

I have a life-size half-length enlargement of a lady painted in oil, which I will exchange for some good illustrated books.— R. A. Seymour, care of the Editor, 54, Paternoster-row.

What will anyone offer him for them-Address, care of the

L. R. D. has two whole-plate specimens coloured in oil.

Publisher.

Referring to the recent solar eclipse, the Mitrodaya (a vernacular Bombay paper) says:-"The scene in the native town was curious at the time of this solar phenomenon. Men and women in their half-barbaric and shabby dress were to be seen going from one temple to another to pray the deity to go to the help of the luminary of the day in his duel with the headless giant Rahu. The hallalcores, who are the dregs of the native community, received charities of gold and silver, copper, and clothes of various kinds. The ignorant thought that these sweepers had the efficacy of freeing the sun from this torment. It shows the Indian society in a stage of semibarbarism."

Amongst the abridged specifications of patents recently published, we find the following:- 925. J. B. Linnett, Birmingham. Producing optical illusions. Dated March 18, 1868. This invention consists in printing or otherwise producing on one or both sides of separate leaves, sheets, or cards of paper, or flexible material, a series of different pictures, in which the object or objects, or a portion or portions of the object or objects, which it is intended shall have the appearance of moving, are represented in different positions, and binding or securing the said leaves, sheets, or cards together, at or near one edge, so that by turning over the said leaves, sheets, or thereof, in their several positions, are presented in a rapid suecards rapidly, the object or objects, or a portion or portions cession to the eye, and the picture of a moving object or moving objects thereby produced.-Patent completed.

When the plate is taken from the nitrate bath, let it drain upon blotting-paper, and then pour upon its surface, two or three times, sufficient to cover it, of the following solution (filtered) :-Honey, 3 ounces, distilled water, 5 ounces. Stand the plate up to drain for a few minutes; then shut it up in the slide, and it will remain sensitive for several days.-Delamotte's Practice of Photography, 1865.

THE PHOTOTYPE COMPANY (LIMITED). THE above newly-proposed company's prospectus is now before us, and the following quotations therefrom will, we think, suffice to demonstrate the importance and promise of the ground it is intended to occupy.

EXTRACT FROM PROSPECTUS.

"This company is formed for the purpose of acquiring from Messrs. Daniel Fruwirth and Abdiel Hawkins, their patented process of phototypographic engraving, and for bringing the same into public use.

"The process consists of a combination of photography and glyphography, by means of which surface-printing blocks can be obtained from any print, drawing, engraving, printing, or writing, without the heavy expenses of redrawing and engraving by hand, and can be rendered available in carrying out the following, amongst other objects, namely:

"I. The reproduction of all kinds of illustrations for the letterpress, suitable for either books or periodicals.

"II.The reproduction of all kinds of fac-simile work, maps, ornamental writing, landscape and other drawings, illustrations for catalogues, pattern books for laces, embroidery, fancy goods, titlepages, autograph letters and music, &c., &c.

"III. The reproduction of drawings for agricultural implements, architectural and railway plans, designs for shipbuilding, and many other purposes.

IV. The process is also available in the reproduction of any rare or unobtainable work, type or manuscript (which can be copied, enlarged, or reduced), and is equally applicable to many other objects connected with the Fine Arts.

"V. The reproduction and enlarging to almost any size, of millions of the finest copperplate and steel engravings (rendering the same available for letterpress), which cannot be so effectually and accurately executed by any other, as by the phototype, process.

VI. The republishing of costly illustrated books out of print, at merely the cost of a few shillings the page."

The projectors argue a large measure of success for their efforts, and tell us The adoption of this process by the great publishing-houses must undoubtedly follow its proper introduction by this company, and it promises fair to open an entirely new field of art-publications for the education of the million, which will be gladly accepted both by the publisher and the public. The opinions of some of the largest publishing-houses and wood-engravers have been obtained with regard to its value and general adoption, and they go fully to confirm the above statement; while the field in art and manufacture, both at home and abroad, for the proper development of the process, may be said to be unlimited."

It would be difficult for the directors to place before investors any reliable estimate of what the profits of such an undertaking are likely to be, depending as they will altogether do, on the amount of work done and the prices charged; and although calculations have been entered into, showing extraordinary profitable results, they refrain from encouraging extravagant expectations, and merely add their belief that it will prove a most profitable undertaking to

investors.

Specimens already executed, together with the fullest information with regard to the company's proposed operations, can at any time be obtained on application to the temporary office, 65, Hatton-garden.

The company will have an excellent secretary, full of the necessary energy, business tact, and publishing experience, in Mr. Dring, a gentleman who projected the first weekly photographic journal, and was for many years its chief proprietor. We wish the new company the greatest prosperity.

Chloride of lime should be excluded from the dark room, says the Philadelphia Photographer, as it will cause pin

holes.

Questions and Suggestions.

TO THE EDITOR OF THE ILLUSTRATED PHOTOGRAPHER."
PHOTOGRAPHING DRAWINGS.—A SUGGESTION.

SIR,-In Mr. A. H. Wall's very good article, p. 419, a mistake or slip occurs at the thirteenth line from bottom of page, the it cannot be dissolved away-it is the unexposed portion which is bichromated gelatine, when exposed to light, is changed so that dissolved away by warm or hot water. I understand Mr. Wall to state the contrary. One difficulty, referred to by this gentleman, in making clear, dense negatives for producing bichromated gelatine copies, is, I think, the following:-Before the exposure has been long enough to give really good blacks readily on development, the light penetrates the negative film and causes "blurring," or "optical halation," thus fogging the parts which should be transparent. Some American writer stated that he found this to be the case, and that for such work he found it a great improvement to take measures to absorb transmitted light, and to give a longer exposure. I have not tried wet collodion with such subjects in this way, but it could easily be settled by experiment.

ARTHUR JAMES.

SIR,-Much has recently been said upon the above subject, and introduction. I think it only just to remind photographers credit has been given to various persons in connection with its that this process was first successfully practised by Mr. Corbin, in, if I am not mistaken, 1859, perhaps earlier. in the usual way; next sensitising in a bath composed of water His process consisted of first pouring the collodion on glass 100 parts, nitrate of silver 1 part, gun-cotton 15 parts, and iodine 1 part. In about two minutes the plate was withdrawn and immersed in rain or river water, washed under a tap, and a solution of iodide of potassium in 100 parts of water applied. Being again washed under the tap, the film was transferred to gelatinised paper with great ease, and after placing the paper, film uppermost, on a glass plate, a preservative solution was used, which is thus prepared:-Ten parts of honey or glucose were added to three of water, and the white of one egg. The whole was allowed to simmer until covered with a thick scum; it was then clarified, filtered, and bottled for use. The film thus prepared was sensitised by floating on a bath composed of 100 parts water, five of nitrate of silver, and the same quantity of acetic acid, crystallisable.

I am not recommending the process, although I have seen results by it difficult to surpass, but only reminding some of your readers-who appear to have forgotten it-of its existence. Perhaps some one will modify it, and then claim a gold medal at the hands of the President of the Photographic Society.

A. J.

Speaking of the few good and many bad lenses sent out by French opticians, Mr. Fry, writing to a contemporary, says: "Now, from my own experience, I do believe that nothing of that kind can be alleged against English lenses. A price is charged which allows for the rigid exclusion of every lens that is even doubtful, or which does not give results up to a certain very high standard. On the other hand, the lenses that are sold at low prices are necessarily of mixed quality; those who have the opportunity and knowledge suitable for trying specific I have seen in tests might possibly obtain a very fine one. lenses costing only about 30s.; but I have also known those Paris a celebrated operator working daily with a pair of card who have purchased apparently similar articles be wofully disappointed." This writer also gives us an extra inducement for purchasing only the best lenses, that if they are taken care of, and you have occasion to sell them, they will fetch almost full value, but we do not think those who have had experience in that way will agree with him.

SIR,-Some letters have appeared in a contemporary complaining that photographers have no means of knowing when they can pirate another man's works without suffering the proper legal consequences; for, as one of these writer's states, they would "be indeed glad if some way could be devised by which photographers might know when a picture or photograph is a copyright, so that an innocent man should not be pounced upon unawares.'

Now, when I take a negative, and have all the trouble and care of selecting a pose, lighting, and studying my sitter, so as to render a good portrait of him, &c., I consider it only fair that I should have the right to supply all copies from that original negative at a fair rate of remuneration, and consider myself wronged when my photograph is put into the hands of one of those cheap, innocent, mechanical dodgers, who copy and print so many dozens of cartes-which libel the original negative, and injure my reputation-for sixpence or thereabouts, unless I have previously gone to the trouble and expense of registering the photograph, with the written consent of my sitter, without which, I believe, my legal right might be successfully contested.

W. H. KENNEDY.

POUNCY'S PROCESS. SIR,-Your correspondent," Arthur James," in the last number of THE ILLUSTRATED PHOTOGRAPHER, puts before your readers a very fair subject for inquiry. If Pouncy's bitumen photographs are permanent, then, he argues, bitumen paintings which have been subjected to the influence of light for years ought also to remain unchanged.

In reply, I would remind Mr. James that the cases are entirely different. Mr. Pouncy uses bitumen of Judæa only as the sensitive medium, not as a pigment. All the superfluous bitumen—that is, all that has not been indurated by light-is washed away by the solvent used to develop the photographs. The film that remains adherent to the paper or canvas is excessively-I may say inappreciably-thin, and seems to be altogether unaffected by temperature. (See article at page 439.) I have reason to believe that in a finished 12 by 10 photograph by Pouncy's process there does not exist more than a grain, if so much, of bitumen distributed over all that area. How could that quantity run or slip over the paper by heat or any other agency?

Painters, I am told, sometimes brush on masses of bitumen on their pictures, both as a pigment and a ground. It is only the external surface of this that can possibly be indurated by light, because this substance is impermeable by actinic or chemical rays. All the bitumen underneath remains in statu quo, and is liable to thermal changes, which, of course, may cause it to "run." Again, if this pigment is used as a ground it may be overlaid with other colours, which prevent light from reaching it and altering its character.

If I have not properly stated the painter's method of using bitumen, I hope Mr. Wall, or some other painter, will put_me right, as I have no practical experience in that art. Yet I do not think a painting containing bitumen in its composition could stand a tithe of the tortures to which I have subjected Pouncy's photographs without damage. King's College.

GEO. DAWSON,

RAINE'S UNIVERSAL PANORAMIC CAMERA.

SIR,-In your last number, Mr. Sutton makes some ingenious suggestions for simplifying my camera by applying a fixed, instead of a movable, serrated band. This arrangement is the same as in Prout's patent camera, where it does not answer the purpose. He also suggests moving the serrated band half a tooth. He will find, if he tries this method, that it will leave marks on the plate.

In your issue of Sept. 25th, he says, in describing the camera, that two lenses are used; but the camera is made with one lens and a sliding front; he states that the stereoscopic pictures taken with it are seven inches square; whereas they are of the ordinary size, the bellows body expanding from three inches to suit lenses of short focus. He further states that this mode of taking panoramic views involves an error in principle, because it does not suit all subjects. Now it is well known that the panoramic lens and the pantascopic camera, when used for flat pictures, are

not adapted for all subjects; and consequently, for the same reason, they involve an error in principle. In practice it will be found that my camera is adapted for a larger number of different subjects than any other camera yet introduced. It is a fact that there are many subjects that no panoramic arrangement will represent correctly, for example, the front of any of our cathedrals. With my camera, I remove the partition, and use the Ross's doublet in the usual manner, and thus get the widest angle on the plane perspective. Richmond, Yorkshire.

THE GODDARD FUND.

JOSEPH RAINE.

SIR,-You have been doing good service to the cause of honest photographers, by exposing the conduct of those persons --I cannot call them gentlemen-who have so mismanaged (appropriated may I say?) the moneys collected for poor old Goddard. Has Mr. Goddard left any heir or executor who can prosecute those fellows who collected and retained his money? If so, the right party should at once prosecute the collectors, else it may be too late. The subscribers to the fund, I am told by my legal adviser, have no ground of action, except by a very roundabout way which includes a criminal charge of obtaining money on false pretences. Although a subscriber to the fund, I will not undertake that responsibility, because I think the promoters of, and the collectors for, the scheme meant well at first, but acted badly afterwards, when they found so much money in their hands.

A SUBSCRIBER.

SIR, I am told it is a sense of dignity-in no sense anything but nonsense-which keeps the above from either explaining or apologising for their conduct. If this is true, the following quotation from Zimmerman may throw light thereon:"Apply to little people in the season of distress, they instantly become great; they are surprised at their own importance."

I think nothing speaks less for any class of men than a want of public spirit, a slavish indifference to wrong-doing and injustice, such as photographers have displayed in not more energetically seconding your efforts, outside the journals, to enforce the trustees to account for the money entrusted to them, and allowing men with such a stain upon their characters as men of honour, or even common honesty, to retain posts of

honour and the reins of power in connection with photographic societies and journals, from which, by the most questionable of means, they contrive to oust all honest men who have courage enough to stand up for the dignity of their class against trade puffery, quackery, or cliqueism.

To Correspondents.

J. COLLINS.

OLD PUPIL. Your letter was received and acknowledged last week. Mr. Dawson says in reply," I really do not know what my good friend means when he says that his sensitive albumenised paper sometimes pulls up with it the negative film, with which it has been in contact. I can only understand his assertion in one sense, which is, that he has been printing on moist sensitised paper, which is likely to carry up the collodion film, especially if great pressure is used. I know no other rational explanation, unless more particulars were submitted to me."

Then all will be right. For old stains on the skin, you may have to rub off the greater J. R. S.—(1) Get a cake of Cleaver's photographic soap and rub well for new stains. part of the cuticle with pumice or a scythe-stone before you reach the bottom of the silver contamination. (2) Ross's No. 3 card-lens for the work you mention as "particular." Any good single objective is suitable for the other work.

SALOMON-ADMIRER.-(1) Encaustic paste for pictures is as old as the hills, at least as old as Pliny's old memories, and the traditions handed down to him. It was practised long before the commencement of the Christian era, for the purpose of giving transparency to the shadow and general brilliancy of effect. Bees'-wax, then, as now, was always employed to get particular effects of transparency. (2) There is no particular virtu: in the lenses you name, except that they are not so good as those manufactured by our most eminent optician, Mr. Ross. The differe.ce of price, however, might be an obstacle to you.

OLD WOMAN.-The title you adopt is an odd one, and certainly a misnomer. Your question, on the other hand, is very apropos to the matter you inquire about. Not 480, but 4378 grains are the legal weight for an ounce of nitrate of silver. You have been apparently served properly.

PAUL PRY.-The writer who signs "Respice Finem" is not Mr. Robinson, but Mr. Valentine Blanchard.

W. H. R. says" Is it not odd to find that Mr. Beattie's appeal, which was inserted gratuitously in your own pages (and in the British) appears in the organ of the clique' as an advertisement?"

J. C. says "I referred my new assistant the other day to the British Journal Almanac of 1868 for information about the number of grains in an ounce. He came back and said, It's 407), sir.' You goose,' I rejoined, look again, and be sure you learn your tables correctly before you speak to me more.' He came back again with the book in his hand; and there, sure enough, was printed, under the head of avoirdupois weight, 16 drachms equal ounce, equal 407 grains. When such mistakes are committed in handbooks for general and common information in photographic matters, what greater mistakes may not occur in the other more general matter?" In

reply, we have only to say that such things will happen when a book is got up in a

hurry, or without proper editorial supervision, as seems to have been the case in this instance.

Q IN A CORNER.-We will do what we can to get you out of it. The hole you have accidentally made in the painting you had to copy, must first be carefully filled up with white lead mixed to a proper consistence with linseed oil. When the hole is thus stepped, as it is technically called, and smoothed over with a palette-knife-a paperknife will do-clean off any of the white at the sides of the hole, and mixing a little oil colour as near the tint of the surrounding parts as possible, stipple it carefully over until the place closely resembles what it was before the accident occurred. Keep the painting as long as you possibly can, as it may so change in the process of drying as to require retouching before you send it home.

NO CHEMIST.-(1) Pyrogallic acid is really a neutral substance. Tois, therefore, upsets all your calculations. (2) Glacial acetic acid is the most concentrated form of the acid known. (3) Chloride of mercury is not pure as usually sold, but it is sufficiently so for the purposes to which it is applied in photography. (4) You may purify the animal charcoal you have purchased by repeated digestions in hyd ochloric acid. (5) A little hydrochloric acid exposed to the air will quickly counteract the effects of vapours of ammonia in your dark room. (6) Nitrite of silver is always present in stronglyfused nitrate of silver.

A CLERGYMAN states that Mr. Fennessy's idea of Adam being a perfect creature is a very old one, long since, and necessarily, abandoned, and points out its inconsistency when judged by the evidence of Holy Writ; but we have already devoted so much space to another letter, by "Diogenes," that we must ask our correspondent to forgive us for keeping his reply out of print.

G. B.-A SCHOOLBOY-E. R.-See reply to "Diogenes" and “A_Clergyman.” We really cannot devote so much space as these letters would require to a subject altogether foreign to the nature of a photographic journal.

A BELIEVER.-See reply to "G. B.," and others.

ETCHER. Fluoric acid may be used or the purpose, but remember it is dangerous. Its fumes are very mischievous, and the least touch of it upon the flesh will be productive of a malignant ulcer.

B. J. L.-Nothing is perhaps more constantly or largely adulterated than honey is. See page 356.

A MAN OF WAX.-Our " Gossiping Photographer" says, in reply to your note, "The baseless assertions some writers scatter so recklessly over the pages of certain journals are frequently very mischievous; but the spurious coin you have discovered is such a very little one, that it is hardly worth the trouble of nailing it to the counter. Let it pass."

MOUNT PLEASANT.-If you add a little alcohol to the starch directly after it is made, it will keep good for a much longer time.

D'ANGLETERRE.-To make what is called India-rubber oil, put four parts for ape oil to one of the rubber cut into strips, and simmer over a fire until the latter is dissolved. We have never used it for such a purpose, and shall be glad to know the result of your experiment.

ZETA.-(1) In all probability the spots on your prints are owing to the use of zinc washing-trays. Metallic zinc reduces the salts of silver, and is well known to produce stains on moist photographs in contact with it. If you varnish the inside of the trays, you need fear no bad effects. (2) We have never found any good effect arise from nitrate of soda, or any other nitrate, except that of silver, in the printing bath. You may, however, try for yourself. As to the chloride of gold, we fear your specimen must have been very poor in the noble metal.

DIOGENES (secundus).—You will see the matter you first mention has been treated of elsewhere. In reply to your query, we are not aware that collodion for transferring regatives is to be had in the market. You can easily extempo ise a sample by adding about three minims of castor-oil to each ounce of plain collodion, and then shaking the whole up.

F. H-D.-1) Nothing is better for wiping your lenses than a piece of very soft chamois'-skin, as it is less likely to scratch them than any other substance. (2) We do not know what is the largest size of albumenised paper sent out by the trade. We have no doubt, if it is specially ordered, you can obtain it of almost any size. (3) For transferring, level your glass on a stand before applying the collodion. You seem to have added too much castor oil; correct the error by mixing with the collodion a plain sample without the oil.

G. S. is informed that the India-rubber automatic syphons can be purchased at Solomon's, Red Lion-square; but they will have to be specially ordered, if required of extra length.

PHOTO-ENGRAVER.-A process was long since published by E. Robiquet, in the course of which he increased the relief by the use of lithographic ink. The process was thus described:-"The drawing was made with a metallic pencil (zine or lead), and afterwards exposed as you would expose a daguerreotype plate, to the vapours of iodine. When the lines assumed an orange-yellow tint, due to the formation of an iodide of zinc with excess of iodine, the image thus surcharged with iodine was quickly transferred to a zinc plate, perfectly cleaned, by pressure on a lithographic press. Then a solution, composed of lithographic ink, diluted in soapy water, was poured upon the plate, which was afterwards washed in plenty of water. The ink was thus removed from the plate, but adhered to the lines. After it had been allowed to dry, a proof could be obtained from it in the lithographic press, in the ordinary way The principle can be readily applied when your lithographic stone is used in lieu of the zinc plate. DIOGENES sends us the following letter in reply to Mr. Fennessy's" Purposes of Science." It must be obvicus to all our readers that a discussion of this nature would be altogether apart from the purposes of photographic journalism, and we therefore insert it in this column, rather than in that set aside for " Replies and Discussions," premising that, although we shall permit the gentleman attacked to reply, should he think fit to do so, no further letters on this subject will be suffered to appear." Diogenes" reminds us of O. W. Holmes's description of the men of facts," who "wait their turn in grim silence, with that light tension of the nostri's which the consciousness of carrying 'a settler,' in the form of a fact or a revolver, gives the individual thus armed." They play a useful, but it is not a great part, in the school of progress. Diogenes says:-" Sir, whatever 'the purpose of science, may be, it can only be accomplished by its advancement, which is diametrically opposed to unproved contestable assertions, such as nine-tenths of those contained in Mr. Fennessy's article. The gentleman named declares that all profane study should be subservient to the scriptural teaching, that the Bible should be our textbook and our lamp. As all other dogmatic assertions made by writers who assume that they are pre-eminently religious because pre-eminent ly credulous, and as pre-eminently intolerant, this one most needs to give the very reasonable scientific requirement of evidence before it can be accepted. The idea of receiving as a guide and textbook any volume which says the sun and moon stood still, that the earth was made in six days, and that a being perfect in physical beauty, and perfect in intellectuality,' should have tumbled down to the contemptible sphere which your contributor indicates, merely because he eat an apple, is too ridiculous for acceptation by those genuine men of science to whose honour able name and position claim is laid by countless illogical ungifted babblers, whose dogmatical endeavours and pompous quotations could at best but make sweet religion a rhapsody of words."" To our thinking there is nothing more absurd or improbable in the Biblical statements than there is in the erroneous notions of cause held by some philosophers, who attribute design to unintelligent things, and ascribe enity and power to mere abstractions. The dogmatic assertions of those who believe in these

absurdities are not, in our own estimation, in any way superior to the wildest fancies of the grossest superstition; and we are sure many "men of science"-self-styled-think themselves pre-eminently superior to the humble and child-like worshipper of God in His works, simply because they are pre-eminently credulous and pre-eminently intolerant, and not because they truly know more of the mysteries of creation than the religious thinker do s. As Mr. Fennessy justly says, it is not the great philosophers, the deep thinkers, who ridicule these things, but the little cold-blooded carpers and quibblers, who don't believe in hearts, and who do believe in a foot-rule and a pair of scales, by which only, in their estimation, all facts of all kinds can be surely and properly demonstrated. We do not accept the Bible as a scientific authority, and we suppose no other sen ible person does so accept it. It could never have served, or serve, its great and noble purpose had it been such a work. If it had given us science in its perfection, the Jews would have had as much trouble in understanding it in their day as we should have in understanding it in our day; for it is not pretended, great and wonderful as our modern philosophers may be, that they have parfected science and know everything, although they speak and write as if this were the case. The Bible takes up the grea: riddle where the Materialists leave it. Where they invent a name, and say that name is the cause of such or such effect, this Great Book points out the love and goodness, the power and purpose palpably governing all teese things, and says, therein is demonstrated the Great One Cause of all things; and so, while stirring the hearts of all, great and small, learned and simple, to humble love and worship, gives new life and power to all the nobler impulses and instincts of our common nature, Increases our happiness, and affords us all those opportunities for advancement in art, science, and literature to which we owe our present position as a nation.

A FRIEND TO THE "ILLUSTRATED."—(1) The acid added to the hyposulphite of soda would be apt to precipitate sulphur. (2) Use god bottle India-rubb.r, rejecting the darkest portions, and dissolve in purified benzol. (3) We prefer rice starch.

G. KEMP.-(1) White wax is commonly adulterated with tallow and stearine : in its purest condition its colour more nearly resembles that of bees'-wax. (2) Always use the very best mounting boards, the more common samples contain bleaching compounds injurious to the photograph.

MOUNTING PRINTS.-"G. S. W." recommends the use of gum and gelatiue, mixed in about equal parts, and containing a small piece of camphor, to prevent decomposition, as the very best mountant he has met with in the course of many years' experience. It is not a new one.

A WORKING OPERATOR.-Isinglass is better than gelatine. (2) Glucose, or, in other words, grape-sugar, was recommended by Maxwell Lyte for increasing sensitiveness, and causing the plate to retain it for some hours, many years ago. Messrs. Spiller and Crookes recommended nitrate of magnesia for serving the same purposes. (3) We never saw satisfactory prints produced by the formulæ you refer to, which involves an error of principle.

STUDENT (1) Full information concerning the early processes of etching and engraving Daguerreotype plates will be found in "A Treatise on Photography," by N. P. Lerebour, translated by Mr. J. Egerton, and published by Longmans and Co. in 1834. If you cannot succeed in obtaining it, we shall have pleasure in lending you ou copy. Mr. Fizeau's process is merely referred to in a footnote as a very successful one. (2) Photographic societies are far from being so numerous as they were a few years ago, when not less than eighteen such existed in apparently flourishing condition. (3) We think it probable that the South London Society will take some action in the matter; if not, we must agree with you in thinking that it can be no great honour to have founded such a body, or to have been in any way officially connected with it.

MR. PEARSON'S WIDOW.- An Operator" sends one shilling's worth of stamps for this fund. We wish Mr. Beattie's appeal had been responded to more liberally. fatherless,' suffering the evils of extreme poverty? Can't some more of our friends spare a few pence or shilings for "the widowed and

The barometer readings during the past week have been steady. Although showing a tendency to lower some few days since, there is a slight increase of pressure this morning, due, no doubt, to the wind being in the northerly quarter. On comparing this week's readings of the minimum thermometer with that of last week's, we find the expected decrease of temperature, as mentioned in last week's report, although the maximum or day temperature has increased. There has also been a slight decrease in the humidity for the past week. The present readings of the instruments indicate no important change in the weather. Should barometrical pressure increase, and the wind continue in the north, fine, dry, but cold weather may be expected, with frosty nights.