The Optical Magic Lantern Journal (February 1892)

The Optical Magio Lantern Journal and Photopraphio Enlarger. i) conduct the spirit readily. The oxygen supply | is attached at O,and is blown through the flame at C against the cylinder of soft lime D, which, of course, is placed on the pin E. When house gas cannot be obtained and a limelight is required, this form of jet will be found to be the most convenient, especially to the inexperienced. Perhapsthe most frequent cause of failure with this form of burner is the rapidity with which, in the hands of some, the wicks burn away, for even in adjusting the wicks for the spirit flame there is a right and a wrong way. If the wicks are allowed to remain upright the stream of oxygen will play upon them as well as on the | lime, and so they are thus rapidly burned away. The size of the spirit flame is, in consequence, decreased, whilst the incandescence of the lime is diminished accordingly. The wicks should be well pulled out, and then bent sideways ; this allows the stream of oxygen to blow on the flame only, and this is the chief secret of success with the lamp. It must always be borne in mind that the smaller the flame (to a certain extent) the less the incandescence of the lime, and consequently the more diminished will be the light. We may here say that there are other means of obtaining lime-light without hydrogen or house gas, but of this we will speak later on in this series. 30% Jets for Saturators. By ALBERT W. SCOTT. In order to obtain satisfactory results with saturators, it Is essential that a properly-adjusted jet be used. The ordinary jets used for coal-gas frequently fail when employed with ether, because the arrangement which may effect a thorough mixture of two light gases like coal-gas and oxygen, is quite inadequate to mix the light oxygen with a very heavy gas, such as the ether vapour is. The gases not being properly mixed, we have a great waste of gas and vapour; for it is only in the middle of the nipple where a mix| ture exists. On one side of the nipple there is a current of pure oxygen, and on the other side a current of ether vapour. The remedy for this is simply to lengthen the curved tube between the mixing chamber and the nipple ; this will give the gases more time to get mixed, before issuing | from the nipple. When the light flickers, it is caused by the heavy vapour continually tumbling in waves to the bottom of the mixing chamber, the light oxygen floating over the vapour. This is easily cured by packing the mixing chamber full of ; wire gauze, or with cotton wick damped with > glycerine, or with pumice grains. If intended to | be flame proof, the packing of cotton or pumice grains should be about fin. in thickness. With regard to the nipples, it is quite correct that the smaller the bore is, the less liable is the jet to give snaps and pops. But, on the other hand, the smaller the bore is, the weaker is the light; hence we must find a happy medium. which will give safety with sufficient light power. The size of bore available depends upon the fluid used; the more carbon it contains, the larger is the bore available. Hence coal-gas will work with a larger bore than ether, and benzoline with a larger bore than coal-gas. Pure hydrogen requires a very small bore, about one-eighteenth of an inch diameter being about the maximum. Ether may be put at one-sixteenth maximum ; benzoline and gasoline at one-fourteenth of an inch. ° The largest bore the writer has used was a one-twelfth with gasoline in the warm-air satu| rator; the incandescent area of the lime was about 2in. long, and 1}in. wide ; it was a splendid light of over one thousand candle power, but rather too large for lantern work. With a one-fourteenth nipple eight hundred candle-power can be had with benzoline, and this without noise ; thesame nipple gives six hundred candle-power with coal-gas. The maximum light of ether appears to be five hundred candle-power. The ordinary ethoxo light is about three hundred or four hundred candle-power. As an illustration of the effect of a brilliant light on the screen, the writer once gave several exhibitions on consecutive nights at the same place. Collections were taken, and it was found that a light of eight hundred candle-power produced nearly double the amount of cast that was obtained when using a light of four hundred candle-power. 10: Messrs. WALTER GRIFFITH AND Co., of Highgatesquare, Birmingham, intend shortly to open commodious central premises at 5, Union-passage (New End-street), Birmingham, for the sale of photographic materials and apparatus. Mr. M. O. Suffield, who is a qualified chemist, photographer and lanternist, is to assume charge of the new depét. This firm will also be prepared to accept engagements for lantern exhibitions. The Fry Manufacturing Co., of Chandos-street, are the London agents for this firm, and have arranged to enable Messrs. Griffith to supply their enlargements in Birmingham at the same price and promptitude as in London, Mr. ROBERT C. MuRRAY (formerly of the firm of Murray and Heath) having concluded his engagement as organiser and manager of the photographic department of J. J. Griffin and Sons (Ltd.), has within the past few weeks opened new premises at 8, Garrick-street, W.C., for the manufacture and sale of photographic and lantern apparatus. Mr. Murray has many friends in the photographic world, and we wish him every success.