The Optical Magic Lantern Journal (October 1893)

150 The Optical Magic Lantern Journal and Photographic Enlarger. produced. A roughly-drawn diagram produced by a non-artistic but learned professor frequently conveys more real and permanent knowledge than an elaborate drawing from the pencil of an artist whose knowledge of the subject drawn is nil. Some of the drawings which appear in our text-books bear no more resemblance to the object they are meant to represent, than a mole-heap does to a mountain. The cause of this is soon found, the authors not being themselves artists have had to employ others (not acquainted with the subject in hand) to illustrate their works, and the drawings have been made rather to produce artistic effect than to ccnvey real and lasting knowledge. On the other hand, the drawings in a few of our books are worthy, both from their beauty and truthfulness, of being hung upon the line in the Royal Academy. When our text-books are illustrated with engravings made from photosraphs of the actual objects taken under suitable conditions, we shall have made a great step towards perfection. Photography is the willing slave and helpmate to nearly every science, and to none does she offer her help with more certainty of proving useful than in the science of teaching, especially when her wonders are demonstrated with the aid of the optical lantern. The object of this essay is to point out the true position which the optical lantern ought to hold as an instrument of education. The magic lantern (as this now well-recognised instrument of precision is frequently, and to its detriment, called), we have good reason to believe, was first known in a crude form as far back as the middle of the sixteenth century. The first conception of it as a working instrument can with certainty be traced back to the seventeenth century, when Athanasius Kircher, a learned Jesuit, in one of his works, ‘“ Ars Magna Lucis et Umbrie,” not only gives descriptions and drawings of numerous optical contrivances, but shows in a concise manner that he understood the main principles upon which the optical lantern depends. There is but little doubt that a crude form of the instrument was used by necromancers to produce some of their wonders. 2 ; No one person has the honour of having discovered the lantern. Its development from the primitive form has been made by a process of evolution, one improvement being suggested here and another there as the science of optics has been better understood, as our mechanical skill has increased, and as our knowledge of illuminants has become greater. The oil-lamp was superseded by the Argand gas burner; this was in its turn surplanted by the whiter and better light afforded by mineral oil. All these, however, have had to give place to Lieutenant Drummond’s brilliant lime-light. The lime-light, with its recent improvements, is now generally adopted as being the most suitable for lantern work; but even this is in some instances abandoned for the latest competitor in the field—the electric light. The management of the illuminant necessary for the proper working of the optical lantern has for a long period been the great stumbling block placed in the way of its general use for class instruction. Modern discoveries and inventions have, however, to a great extent, helped us to overcome these difficulties. We have now on the market steel bottles containing compressed gases; these have enabled us to do away with the cumbersome, expensive, and dangerous gas bags. Instead of having to make your own gases (an operation attended with considerable danger) we can now purchase them at so cheap a rate, that the home manufacture of them is rendered unnecessary. The prices charged for these gases at the present time is certainly high, but with a greater demand they will undoubtedly diminish. The steel bottles containing the compressed gases are much more portable, take up Jess room, are very unlikely to be injured, and are much safer than gas bags, and although in the first instance (considering that pressure gauges are necessary for their proper use) they are more expensive; they are considerably cheaper in the end, as they will with due care last a life-time. The gas will keep in them for an almost unlimited time, even when they are not used; whilst, unless frequently used, gas bags must be emptied, and must be taken the greatest care of, otherwise they rapidly deteriorate and allow the gas to leak. The bottles can also be hired at a reasonable rate from the manufacturers of compressed gases. For class demonstration a single lantern is all that is required, the best pattern being one in which the brass draw tubes attached to the