The Optical Magic Lantern Journal (April 1897)

The Optical Magic Lantern Journal and Photographic Enlarger. 63 The '‘ Magic Lantern Journal” gradually gets nearer the North Pole. During a visit from Mr. A. H, Saunders, of Heath Street, Birmingham, he informed us that through his advertisements in the Maaic Lanrern JournaL he has made customers for making and colouring lantern slides at many remote parts of the world, amongst them being one at the village, town, or station known as Nipper’s Harbour, Franz Josef Land, this being the most northern inhabited station, and where vessels rarely call oftener than once in five or six months, so it is quite evident that this journal does not reach that destination with great regularity. There, often for want of a better substitute, whale oil has to be resorted to as an illuminant for projecting the lantern slides. co te A Protest against the Lantern in Church, ‘—A correspondent writes: ‘I am sorry to see that in your journal you report meetings held in churches, in which the magic lantern forms a prominent feature, and I have on several occasions read in your columns that you seem to glory in this ‘march of progress’ as you termit. I hope, sir, that you will see your error in thus advocating such desecration; it is nothing }ut the influence of the Devil, etc.” There is a good deal more of this sort of cant, and we can only reply that the suggestions are foolish. ~ % * Cinematograph Films.—Purchasers of the above should see the new catalogue just issued by Mr. Philipp Wolff, of Southampton Street. It is printed in three languages. Acetylene Gas. (Contiued from page 46.) Tar decomposition of liquid acetylene by simple ignition is relatively slow and appears to take place in two stages—one corresponding to the decomposition of the gas, and the other that of the liquid. In an experiment where the liquid occupied -15 of the containing veasel,a maximum pressure of 1,500 kilogrammes per square centimetre was recorded. Experiments were made to determine whether the ie ae gas or liquid could be exploded by mechanical shock. impact ofa bullet which pierced the containing cylinders, was the acetylene exploded. In the case of liquid acetylene an explosion followed the shock after a short interval, but this was shown to be due to the ignition of the escaping gas, after admixture with air, by a spark from the breaking metal. A small charge of fulminite of mercury, fired in the middle of a cylinder of liquid acetylene, detonated the liquid and shattered the cylinder in the manner of a true explosive. The authors describe the conditions under which danger may arise by casual elevation cf temperature The results were, strictly speaking, negative. | Neither by a fall, nor crushing with a ram, nor by the | during the manipulation of acetylene. In the first place, they note that in generating acetylene by the action of a small quantity of water or excess of calcium carbide in a closed vessel, the carbide may become incandescent and lead to the detonation of the gas. Sudden compression of the gas in filling cylinders, or in admitting it into a regulating valve, may likewise raise the tempcrature to the point of danger. A sharp mechanical shock breaking the containing vessel may cause sparks capable of firing the explosive mixture formed by the escaping gas with the external air. In Le Matin, of the 29th October last, there is a paragraph recording another explosion of acetylene, which took place about 10.30 on the previous Tuesday morning. | A gentleman named Gervais had fitted up for the lighting of his house 4 cylinder of acetylene, which exploded and seriously mutilated a tinman and his labourer who were at work upon the premises. This explosion appears to have been duc to the use of liquid or compressed acetylene, and corresponds, so far as the somewhat meagre details of the accident would indicate, to the explosion in M. Pictet’s works. A third explosion: of liquid acetylene, resulting in the death of four persons, took place in the Berlin suburb of Moabit on Saturday afternoon, the 12th of December. Ag the use of acetylene is prohibited in Germany, owing to its supposed explosive character, a chemist, named Isaac, had for some time past been making experiments with a view to deprive it of that dangerous quality, and had succeeded so well that he was recently in a position to show his invention to certain high officials, who: were greatly struck by it; while the Emperor, who is kindly interested in all new discoveries and inventions, had intended to hear an account of it from him on the following Wednesday or Thursday— indeed, it is reported that His Majesty intended going to the laboratory shortly. A Berlin correspondent of the Standard adds that Herr Thielin, the head of the Imperial railways, expressed a desire to see the process in Herr Isaac’s laboratory. And the inventor, who had hitherto made experiments only on a small scale, made preparations to show a large quantity of his purified acetylene, the light of which is said to be about three times as brilliant as that from an incandescent gas burner. He accordingly compressed it in a large iron or steel tube by the enormous pressure of about 100 atmospheres, and the tube exploded, blowing him and three of his workmen to pieces, and causing a report which was heard within a wide circuit. The Daily Telegraph correspondent telegraphs: ‘ An aniount of damage was also done to the apartment, and to some of the surrounding houses, a few of the inhabitants of which narrowly escaped being injured as well. As all persons engaged in the laboratory have lost their lives, there is no clue at hand to show the immediate cause of the catastrophe, and the discovery itself was the secret of the inventor, who has perished.” Here then are three terrible accidents resulting in a serious loss of life and considerable damage to property all brought about by the use of highly compressed liquefied acetylene, in each case probably manufactured by trained workmen acting under careful scientific supervision, so that the results can scarcely be attributed to carelessness or to blunders committed by men having an imperfect knowledge of the work upon which they were engaged. How then does this method compare with that in which the gas is generated directly from the calcium carbide, and stored and burnt under low