The Optical Magic Lantern Journal (February 1893)

The Optical Magic Lantern Journal and Photographic Enlarger. oo opaque screen with batten and roller. Our room is long {70 feet) and narrow (26 feet), but the width is reduced by a projecting wall in the centre toabout 13 feet. This compelled us to show from the side, with the result that at 24 feet distance, and a 64 inch focus, with oil lamp, our picture if square, was nearly a foot deeper on the side farthest from the lantern. We soon found out the cause and tried to get a stand, but no maker mentioned ‘such a thing; fortunately one of our committee (an old lanternists), came to our help and made a stand, which has answered well. It is very easily put up in less than tive minutes. We have been told by many persons including lanternists, that it isthe best screen and stand they have seen. The same person also planned out a box to hold lantern, oil can, reading lamp, slides, tools, and in fact everthing we are likely to require with an oil lantern, including a stand 5 feet igh, which will carry two lanterns and is perfectly rigid; it has also a central shelf where the operator puts his slides and a small lamp. My own experience is that with an oil lamp the Opaque screen increases the brilliancy of the picture at least 20 per cent, and for local work with a good stand, should prove a-great advantage to many who are now bothered with the creasy ordinary screens. IJ have not sent details as I have no opportunity just now of consulting the inventor. Thinking, however, that the idea as to what could be done ,might be some small public benefit I venture to send them, and at the same time thank you for the many useful suggestions I have | received from your capital paper.—Iam, Dear Sir, Yours truly, T. ANNS. FILM LANTERN SLIDES. ‘To the Editor.: Sir,—Now that cut films have been brought to such perfection both in transparency and quality, I am greatly surprised that some enterprising manufacturer does not place lantern films on the market, there seems to be no reason why this could not be done at the same price as glass plates (1/a doz.), and there could be little doubt that such films would in a short time take the place of glass altogether, and command an enormous sale. If coated with a chloride of silver emulsion, the printing could be doun in an ordinary printing frame, and the progress be examined from time to time as easily as paper. Then as regards mounting, if the film side were protected with a piece of talc or thin transparent eilluloid, and placed on a mask of thin sheet metal, the edges of which could be turned over the films and so bind them together, it would form a most compact and unbreakable slide. Such slide would have also have the advantage (as 50 of them would only occupy a space of about 3 inches) of being sent in a cardboard box by parcel post, for about 3d; this convenience for persons living at a clistance would be a great boon. . For amateurs who make their own slides, the metal masks could, if cut out of thin sheet Russian iron with a die, be supplied with protit at 2 or 3 pence a dozen, the edges could be turned over sufficiently to allow the films to be slid in from the side, it would then only be necessary to place the side in an ordinary letter press and give it a squeeze to complete the binding. The advantages of such slides from their lightness and freedom from breakage to all those who store large quantities will be at once apparent, and Ihave little doubt a large profit would accrue to any introducers of them at popular prices, such as I have suggested.— Yours, &c., : L. 8. D. WARM SATURATORS. (To the Editor.) Dear Sir,—In November, 1890, I brought a saturator or ether vapourizer, and have used it ever since. I must say, owing to reading so many alarming accounts through the use of these articles, I have often quaked very much. I think every exhibition I have given this season, I have hissing. pops, and some very loud reports. Once when using my lime boxes for tableaux, I had to ask the audience to give me } hour to myself; (as it was a private house this was soon done, and the room cleared,) I really thought I was yoing to have an explosion. The fault I found was I had put far too much ether into the vapourizer, upon}emptying out nearly a pint, the whole thing went quite smooth, except the hissing. This season I thought I would try warming the vapourizer, and had a tin can made about 18 inches long and 8 inches diameter, this I fill with very hot water (before leaving house), place it between the two tubes of saturator, the whole being in a box and packed with wadding. I can assure you it is quite a comfort to use the lantern now, the light comes at once, and the dissolver acts beautifully.— Yours, C. DALES. P.S.—The tube from the saturator should be held up in some way so that the condensed vapour cannot run back to vapourizer, or a jerky light will be the result, should the exhibition be of wny length, and the room cold. A REPLY TO Mr. THOS. FLETCHER, ON CONDENSERS AND EXPERIMENTS WITH THE LANTERN. To the Editor. Srr,—In writing in your January number, Mr. Fletcher calls attention to some remarks of Mr. W. H. Harrison in the December number, in which the latter gentleman recommended a triple condenser, but Mr. Fletcher says that *‘Mr. Harrison evidently forgets that this form of condenser although useful for common slide showing, is very objectionable when the lantern is used for physical demonstrations,”’ and continuing, Mr. Fletcher states, “Cif the double plano convex condenser be used, the front of the apparatus can be made to swing back, and the front half of the condenser removed and put into the vertical arrangement, without the necessity of shifting the lime dangerously near the condenser, dispensing also with an extra condenser and consequent loss of light.” Well, one does read funny things sometimes, but I don’t remember reading anything so amusing, since one of your contributors a few months ago stated that the double condenser supplied by the firm with whom he is commercially engaged, and called their ‘‘ universal”’ condenser was equally suitable for all objectives of from 4 to 12 inch focus. Of course in the latter case it was simply an advertisement, got in the wrong column by disguise, but in the case of Mr. Fletcher making such a misleading statement, and his endeavours to set Mr. Harrison right, there can be only one ‘conclusion. {[ would therefore refer him to my paper on lantern condensers, recently published in these columns, or I shall be pleased to sendhim acopy oi it. And now I ask the right in self defence, for stating, even in these columns, that I manufacture a triple condenser far more suitable for physical demonstrations, than any double condenser can possibly be, the front lens (next the light) is a thin miniscus for the purpose of collecting rays of light at a wide angle, the middle lens parallelizes these rays, and the back lens can be entirely and ; instantly removed from the outside, without interfering | with either of the other two lenses, or opening the