The Optical Magic Lantern Journal (December 1891)

187 The Optical Maglo Lantern Journal and Photographio Enlarger. desk, light, and stand for a lecturer. one end of a small stand and liberating a catch the legs of the stand fell into position, next a Russian iron lantern (which also acts as a box for fifty slides) was set] upon a square head at the end of stand, a shade was then hinged back from this box, a flap, hinged into three, was opened up and hooked on to the lantern, the brass rod which carries a curtain was passed through two holes, and we had a desk and lamp which we value highly. The curtain which hangs to the ground gives the whole thing a substantial appearance. Wray's CATALOGUE of photographic lenses is to hand. We observe that this firm (North Hill, Highgate, N.) is making a special feature of iris diaphragms, aluminium settings, casket lenses, and of lenses for hand cameras. These latter have a particularly neat appearance, are made of Jena glass, and are provided with either iris diaphragm or Waterhouse stops ; the full opening of these lenses is F8, at which aperture they define with great sharpness. Numerous styles of lenses are shown and described, and at the end of the catalogue is a table giving the angle subtended by any lens oa the ordinary sizes of plates. — New EFFECT SLIDE.—Mr. Underhill, of Croydon, has produced a set of Sandringham Hall, showing it by day, moonlight, and winter with snow effect, and also the hall on fire (Nov. 1, 1891). & PHOTOGRAPHY IN A NUTSHELL” has reached its fourth edition, and has been enlarged and to an extent rewritten, consequently it will be found more interesting than ever. The book is published in the interests of Mr. Wm. Tylar, of Birmingham, who devotes about four dozen pages at the end to a description of the numerous goods in which he deals. The price of the book is one shilling. TALES WITHOUT WorDS.—Five books of humorous sketches have been received from Messrs. Morison Brothers, 99, Buchanan-street, Glasgow. They include “A Fishing Adventure,” “A Bicycling Adventure,” “A Shooting Adventure,” “A Boating Adventure,” and ‘The Ubiquitous and _ his Portable Dark Tent.” These will be found admirable subjects for reproducing as lantern slides, and will keep the juvenile portion of an audience (and for that matter the adults as well) in roars of laughter. ‘These humorous books of sketches may be obtained at sixpence each. StipES.—A humorous coloured set, illustrating « How Bill Adams won the Battle of Waterloo,” is now being issued by Messrs. Levi and Co., London, who supply wholesale only. This set, with the accompanying story, will be found to be most laughable, and is specially brought out for the juveniles. DESIGNS.—From particulars and prices obtained from the catalogue of Mr. F. Weeks, 21, Thorpe-road, Forest Gate, E. We observe that designs for slides can be executed from five shillings. The set of slides entitled, Temperance Picture Gallery, issued by the Band of Hope Union, have been made from Mr. Weeks's designs. By grasping | Correspondence. RE CLICK IN BEARD'S REGULATOR, [ To the Editor.) Srr,—The noise is undoubtedly caused by the coils of the spring not clearing each other properly in compression, and therefore cause the click in passing each other. Or the regalator perhaps requires readjusting. If “L.P.D.” takes cover off, and holds his finger over outlet, and turns gas into regulator, he will see the height the bellows expands to; by holding the cover alongside he will see if the expanded bellows equals the height of cover, if so, it requires adjusting. — Yours, &c., R, R. BEARD. 62, Alscot-road, Bermondsey, S.E. LANTERN MICROSCOPE. [To the Editor.] Srr,—Kindly permit me to saya few wordsin correction of Mr. Chadwick's paper on “ Leach’s Lantern Microscope,” reported in the issue of November. That Mr. C. is considered a great authority on photography and the management of the lantern every one folly admits, but judging from his remarks on the lantern microscope, he has not. ventured very far in the microscopic world. As one who constructed and worked the lantern microscope several years before even Mr. Leach, I think I am able to judge what such an instrament will do. In the first place, Mr. C. is against every authority regarding magnification, Extreme magnification, such as Mr. C. suggests, is condemned by every authority of note. both for the microscope and the lantern microscope. That the magnification which enables the observer to see all the details of an object is the largest to which it should be subjected, anything beyond this defeating the purpose. Mr. C. says that with his arrangement high powers can be used for class and other demonstrations, although he has previously stated that the arrangement of condensersis only adapted for objectives of foar-tenths of an inoh, which is by no means a high power. Mr. C. cannot surely be ignorant of the facts that lantern microscopes, of whatever make, have long been discarded by the college au thorities where high powers are required. I see, too, that he has come round to my views, and does not recommend the use of special objectives. His last paragraph bot two is a contradiction of the previous portion of his paper, where he leads us to suppose that he can use high powers; that is, of course, onefifteenth or one-twentieth of an inch objective with his arrangement, simply because he uses an alum trough. What he says is simply this, in order to use a high power requiring a large amount of light, interpose an alum trough, which stops 50 per cent. of the light! Mr. Chadwick does not seem to be aware of the fact that it is possible to focus the heat rays at a point beyond the luminous rays, and thus avoid all heating of the slide. I should like to inform Mr. Chadwick that the substage condenser, of which he speaks, and the way of interchanging the objectives, was used by me more than sixteen years ago, and shown to Mr. Leach in 1876. In conclusion, Mr. Chadwick says that lantern microscopes, which have no alum trough, are self-condemned. This I d-ny. I do not use an alam trough, and have never melted a slide.—Yours truly, J. A, FURNIVEL. Manchester. ROLLING CURTAIN SHUTTER. [ Lo the Edztor. | S1r,—In the conclading paragraph of an article in last month's Optical Magic Latern Journal, the writer (Mr. G. S. Thompson) says, “ Toat as I do not know of any other shutter combining these advantages, I have patented