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July 16, 1880.] THE PHOTOGRAPHIC NEWS. Dublin, have inspected his reflector, and are in a position to make others of a similar nature ; but, as our readers will observe, there is nothing particularly difficult in the way of constructing the apparatus. Mr. Laws has tried naphthalising his gas in order to increase its brilliancy, but the results of his experiments in this direction show that there is little if anything to be gained by such means. We may men tion, by the way, that according to the Act of Parliament, gas supplied in London should have an illuminating power of not less than sixteen sperm candles, employing a standard burner, and further, that per 100 cubic feet there should not be more than ten to twenty grains of sulphur, and not more than five to ten grains of ammonia. But in the provinces the standard is scarcely so good. Mr. Laws speaks highly of gelatine plates for ordinary studio work. He has employed the silver'bath scarcely at all this year, and does all his daily work with dry plates. He employs the oxalate developer, made up according to Eder’s simple formula, and makes it a rule to expose no more than two plates on every sitter, so familiar has he become with their qualities. We have to thank Mr. Laws heartily for permitting us to see his very clever gas lamp, and for placing so freely at the disposal of our readers the experience and information he gained at the cost to himself of much labour and expense. Next week the “ At Home” will be “With a Peripatetic Photographer at St. Cloud.” THE OPIICAL LANTERN. BY C. G. CUTCHEY.* Mv paper this evening may seem at first sight a little out of season; but as the lantern is so much allied to photo graphy I must plead that as my excuse. There is still a pre judice against the lantern by “ children of an older growth,” as a thing really only adapted to the amusement of the very young—a prejudice I cannot myself entertain, as it is, without doubt, an instrument not only of amusement, but of instruction. I know it is the correct thing to put down every invention to an Englishman, bo suppose I should not bo in order unless 1 claimed the lantern as of English origin, Roger Bacon having the credit of its invention in the twelfth century. However, 1 think there can be little doubt that many of the (supposed) supernatural apparitions of the “ dark ages ” were the work ot the lantern, and that the so-called " wizards ” largely used it to aid them in their deceptions. But it was not wizards only who used it, for we read that a Sicilian priest produced phantom figures by it in the Amphitheatre of Rome, in the presence of Cellini, a Florentine engraver, who died in 1570. It was much improved by Kircher, a Jesuit, who describes it iu his Latin work, entitled “ Ars UagnaLucis et Umbra." This lantern consisted of a wooden box, enclosing an oil lamp, having an opening in front for a tube containing the lens. It seems to have re mained in this state for nearly three centuries, till Mr. Child, in 1811, pubicly exhibited his invention of dissolving views. Up to this time the lantern may be described as simply a scientific toy, the illuminator still being an oil lamp. The lime light was first used about 1834. About this time Messrs. Carpenter and Westley were fitting up the Bond Street Theatre in a most sumptuous manner for its extension ; but in the meantime, Mr. Carey, of the Strand (who had just made apair of lanterns for the Polytechnic Institution), took a largo room in the Strand (opposite his premises), formerly used as a billiard room, and exhibited the lantern for the first time with the lime light. This light was afterwards used by the Poly technic and similar institutions. It was then known as the “ Drummond light,” and had previously been employed for the microscope, but, of course, only in a small way, the gases being stored in bladders, several of which were connected together and a weighted board laid on them. Mr. Carey used glass bottles for the two gases ; he employed the pure hydrogen. Mr. Macintosh, the well-known waterproofer, now stepped in and undertook to make india-rubber bags sufficiently strong to hold the gas. The first bag was used one evening in the ~ — ■ • Read before the South London Photographic Society. shop of Mr. Bates, an optician in the Poultry. It, however, burst, doing some considerable amount of damage to the shop. Mr. Mackintosh saw what was wanted, and afterwards produced a bag that would hold the gas and bear sufficient pressure to ensure a good, steady light. I have now brought the lantern to a period coincident with the youth of most of us, and to a time when the word “ magic ” might almost be said to cease to be applied to it; still much was wanted to make the lantern perfect. We all remember the immense popularity of the dissolving views at the Polytechnic, and how " country cousins ” on a visit to London were taken to see them. Still, superior as they were to our earlier remembrances of the lantern, they did not come up to the mark, the views being very inefficient. But now stepped in our own black art, photography, and then, as if by magic, the whole was changed, I have been told by my friend, the late James How, in whose workshop many of the slides were prepared, that the excellence otthe Polytechnic views was due to photography. The pictures were first out lined on a large canvas, and then photographed to the required size, and hand-painted. I cannot pass on without here alluding to the excellent hand-painted slides of Messrs. Newton, and the photographic slides by our respected member, Mr. F. York. Mr. Dancer, of Manchester, is credited with being the first to use photographic slides for the lantern, he having exhibited some of M. Ferrier’s stereoscopic slides in Manchester. I have now given a very rapid sketch of the history of the lantern, but a few words as to the name. It has long been folt that the term “ magic lantern ” was a misnomer, and it further carried with it thoughts of those abominable daubs, unworthy of the name of pictures, to which we were treated in our early days at all Sunday and other school treats, when a picture of a seaport would answer as well for Gravesend as Southampton, or, with little more expenditure of yellow and red, for some Eastern port. I remember once showing the lantern for a friend who had been a great traveller, and a hand-drawn slide was thrown on the screen, supposed to be a view ot Alexandria. My friend seemed completely thrown out, and requested me to put on the view of Alexandria. Upon my telling him that I had done so, or, ratherthe picture sent for that place (one of a set of a “Tour Round the World”), he said—“Well, I suppose it must be so, as I see the lighthouse ; but that is the only resemblance to the place.” Well, to return to our sub ject. I think all who wish well to the lantern must feel indebted to Mr. Shadbolt, of Manchester, in suggesting that in future we should call it the “ optical lantern.” And now a few words as to the lantern itself. I cannot agree with those gentlemen who advocate the indis criminate use of the mixed jet, knowing full well the danger attending its use. Of course in large institutions like the Polytechnic it is absolutely necessary, as the pictures are thrown on the scieen for a long distance ; still, when a good, clear picture of fifteen or seventeen feet can be obtained by the blow-through or safety jet (as I have often been able to do), I see no need of running the risk of accidents by using the mixed gases, especially as the whole apparatus is, perhaps, placed in the midst of a largo audience. Mr. Cadett, the other night, in “another place,” stated that he had been violently made acquainted with the ceiling of his drawing-room once, when using a blow-through jet, from an explosion of his oxygen bag. This seems to be a most un explainable accident, as it seems next to impossible that the two gases could get mixed with a safety jet. Of course, with care, a mixed jet is safe enough; but it is as well to avoid a dangerous thing, as even such experienced lanternists as Mr. Malden sometimes have their assistants rather unexpectedly introduced to the audience through a hole in the screen. I find the “ excelsior ” limes the best limes I can get. They are hard, and I have frequently been able to use a lime twice. Then, as to the oxygen gas : I find that half a pound of oxide to one and thr e-quarter pound of chlorate a good mixture, and I always put an ounce (about) of bicarbonate of potash in the purifier. This throws down the chlorine, and so preserves the gas-bag. I always use the black bags; I find them more durable, though dearer at first. And now a word as to the care of the bags: always keep them, when not in use, in a warm, dry place ; this keeps them supple. I will not say much on the “ optical" part of the lantern, that being in such good hands as those of Mr. Dallmeyer. I am, however, inclined to think that the portrait form of objective is a mistake, as the light has to pass through the back combi-