The Optical Magic Lantern Journal (February 1898)

24 The Optical Magic Lantern Journal and Photographic Enlarger. with the international code letters, is worked. The signals are projected on to a portable screen, fitted up in the bow of the ship. These signals can be seen at a distance, according to the power of the luminant used and the clearness of the night, Louminant.— Sec llluminant. Lycrum.— A place of instruction by lecturing, an assembly of improvement, etc. MaGic anD Macicau Errects by the aid of the optical lantern are those changed—and seemingly to the uninitiated—super-human actions, which are simple in achievement to all with a knowledge of the optical lantern system. Macic Lanrern.—As to who the actual inventor was of the optically arranged instrument by this name, history is too conflicting t) arrive at any definite conclusion. Writers have ascribed it to various pereonages, from one Roger Bacon, A.D. 1250, and to many others extending over 400 years, until we are brought to the time of Athanasius Kircher, who lived 1620 to 1680. It would seem at even a later date than that above named—indeed, it may be stated with all safety, that the present century was fairly under way before the magic lantern was regarded as anything but the veriest of scientific toys. During the past 50 years, however, inventors and improvers have gone on adding to its uses and utility, giving us instruments of every possible description, some with the very ugliest unpronouncible names that can be conjectured, many with mechanical attachments of ; | A Little Information about the such a highstandpoint of accuracy and completeness that enables the technical educationalist to teach and present his views in a lucid, graphic, and simple way, that without such aid would be impracticable. But as She subject is the one of all others that the pages of the Oprican Macic Lanrern Journat are entirely devoted to, and, moreover, it being the purport of these articles to discuss briefly ad valorem its merits or demerits, it would seem superfluous to dwell upon them here, further than to direct the attention of the reader to the literary matter referred to above, the term Magic Lantern being the pivot upon which the whole of such matter is centered. MaGnetic Corves are shown with much interest in the science lantern, the movements of the iron filings essentially used in the slides and experiments in their transit through the lines of force being highly diverting.— See also Magnetism. Macnetism anpd Macnets.—That scientific branch which treats primarily of magnetic phenomena, the powers and properties of magnets, etc. Magnetism and clectricity have aclose affinity to eachother. The earth is a great big magnet, and from it all lesser Magnets are induced or made. The strongest of magnetic ores is the valuable iron oxide known as magnetite, popularly called in ancient time, luadstone, lodestone, or leading stone; the latter term, no doubt, derived from the fact that it was used as a compass by navigators of early times, Most readers have gleaned from their school books that a magnet may be made by placing a length of flat steel in proximity to the earth, and by giving it a sharp blow in the middle with a hammer, it becomes a magnet. A. P. Laurie, Esq., M.4., D.&c., Professor of Electricity and Magnetism, University Lecturer, etc., informed the writer that this is so. But a permanent magnet can be prepared by simply taking a piece of bar steel—not iron—and by stroking it at one or both ends a few times with a magnet it becomes magnetised. The steel draws the magnetism from the higher power magnet. Experiments may now be per formed by the aid of this new bar magnet in the degree that it possesses the properties of magnetism, and by balancing it on a needle or pivot, one end will at once swing round to that point of the earth's surface known as the North Pole. This end of the magnet is therefore called the N.P. or North Pole, and the reverse end the S.P.or South Pole. By taking a second magnet, and by placing the two north poles together, it will be found they repel each other. Next place the two south poles together, and it will also be found that they, too, repel each other. Now allow each to swivel on its pivot and take its natural course. The south pole of one will swing round to the north of the other, thus proving they attract each other, and that the north pole of cach magnet points to the north of the globe. These simple facts form the fundamental base of magnetism. M4NnaGEMENT OF LANTERN.—See Lantern Manipulation. ManGaNnEsE.—Kuown to the lanternist as peroxide or black oxide of manganese, and used largely in making oxygen gas. It is the most important of the compounds that present themselves in combination in many minerals. The metallic clement, for such it is, is the main factor in many important manufactured preparations, and for bleaching and disinfecting purposes it is invaluable. (To be continued ) somhiats Cinematograph.—No. II. By W. C. HUGHES. better to interject an art picture either from a separate projecting lantern or alternately in the machine itself fitted with such an 3 arrangement, because it is unwise to <" leave an audience in darkness, neither rool! is it desirable to give them the full glare of light from the body of the hall, or it will be difficult to see the cinematograph pictures. After it has been fixed on the sprocket wheel ready for transmitting to the screen, a number of films must be ready to prevent waiting, or they can be joined together and shown simultaneously one after the other. The joint is made by scraping the gelatine from the surface of one film, and painting the bare celluloid both of this and tke piece to which it is to be joined with acetone solvent, and when the surfaces so treated are placed together and pressed with a proper pressing machine they will stick firmly together. A good machine for doing this can be purchased for 30s. The illuminating medium is a very important factor in producing the animated pictures on the screen. The electric light, if available, is the most powerful, the limelight undoubtedly comes next, and with a