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101 THE PHOTOGRAPHIC NEWS. [FEBRUARY 13, 1885. alcohol, when, after filtering through cotton-wool, the emulsion is ready for use. When boiling, care should be taken to keep the temperature just under the actual boiling point, say three or four degrees. Zotes. How much of the silver and gold used by the photo graphic printer can be recovered? Mr. W. D. Valentine tells his experience. In a given time he spent £720 for silver, but recovered to the value of £501 17s. 3d.; and during the same period he paid £274 for gold, but recovered to the value of £101 14s. Id. Those who wish to know how he did this shoidd refer to p. 101. According to the Figaro, a couple, anxious to intimate the fact of their wedding in the latest new way, must use a four-paged enamelled carte. Page one of the little livre lies noces is to be devoted to appropriate floral decoration ; pages two and three to the names of the bride and bride groom, the date and place of their wedding, the expression of their good wishes, and the like ; whilst on page four should be found the photographic likenesses of the lately- married pair in hymeneal attire. Let the notion become fashionable, as all good photographers will hope it may, and the once general public intimation—“No Cards”—at the end of an announcement of a wedding, will be super seded by the still curter one of “ Cartes." There is one difficulty in the way, however. How are the negatives of the bride and bridegroom to be obtained in hymeneal attire? Does this imply a preliminary dress rehearsal of the marriage service, or is the photographer to be hidden somewhere in the chancel or the organ loft ? A wedding party impressed with the idea that there was “ a chiel amang ’em takin’ 1 cartes,' and that faith he’d print ’em,” would find that yet another misery had been added to the marriage ordeal. That commercial paper is liable to contain sulphides, which on decomposition by traces of acid give off sul phuretted hydrogen, is a certainty; and perhaps many cases of fading are due to these sulphides. Ultra-marine, of which sulphides form a considerable proportion, is added f— to the pulp to disguise a yellow tint; while sulphate of lime is largely used as a “ loading " for paper, and when paste-board is made up of such loaded paper, there is considerable probability—indeed, almost a certainty—of a portion of the sulphate becoming reduced to the condition of sulphide, when the card is kept in a damp place. How to test for sulphides in cardboard is the (2,39358 next point. Take a glass tube, closed at one (19259 end, and slightly expanded at the neck—in w short, a test-tube about five inches long; cut up some of the card or paper, add enough water to nearly cover it, and a piece of citric acid as large as a small pea. Now take a disc of paper that will cover the top of the tube, and hang from this, by means of a thread, a slip of white blotting-paper which has been moistened with a solution of acetate of lead ; one part in five or six of water. The whole apparatus is shown by the cut. If there is a very large proportion of any sulphide present, the lead paper will very soon blacken ; but if the proportion is small, the action is less rapid. It is just as well to very slightly warm the mixture by holding the tube over gas or candle flame, but the heat should not nearly reach the boiling temperature ; now set the appar atus aside (in an upright position) and examine it next day. If there is no darkening whatever of the lead paper, one may conclude the card to be free from sulphides. In these days of heroes, when a fresh one springs up every week, the competition between the illustrated news papers eager to obtain a portrait of the latest notability has been unusually keen. It is only after you become celebrated that society demands your photograph, and it would seem that soldiers in particular are averse to being photographed. Last week the agent of a certain paper, at the first intimation that General Earle’s portrait was needed, did not waste time by going to any of the dealers, but rushed off at once to head-quarters—that is to say, to the general’s home. It was still early in the day when he arrived, but, early as it was, some one had forestalled him, and had secured the only portrait from Mrs. Earle but half an hour before. There was no help for it but to retire gracefully. When are we to get an actual photograph of a battle ? Now that correspondents really go into action, a negative of these ene they witness, or at any rate of a portion of it, might be obtained without increasing very much the danger to the “ special.” The additional “ exposure ” necessary, which need be but momentary, would not be his. Doubtless, then, we shall soon hear of the camera being under fire, and whilst a general may have his horse shot under him, our special will be wiring home that his apparatus and reserve of “ dry plates” have been shot all over him. An artistic photograph—that is to say, a photograph which is also a picture—is not the outcome of chemistry and manipulation alone ; but when one sees a fine photo graph it is natural to ask something about the making of the plate. Mr. Dunmore’s " Early Spring,” which forms our supplement, was taken on emulsion made with iodide by Abney’s formula; Mr. Dunmore having, however, deviated to a trifling extent from the instructions. The reader will find some particulars on page 97. Can it be that Dr. Crichton Brown is preparing another surprise for the Public Education Department? It is rumoured that nearly all the children in one of the large metropolitan Board Schools have been mysteriously way-