The Optical Magic Lantern Journal (April 1895)

60 The Optical Magic Lantern Journal and Photographic Enlarger. charged with warm water, the temperature of which was maintained at about 160 degrees by means of a spirit lamp underneath; air from a small gas-bag was forced through the benzoline, which could then be burnt as ordinary gas and used with a blow-through jet. It is obvious that very little advantage was gained in its use since, if two bags were necessary one of them might as easily be filled with coalgas as with common air; although it was urged at the time that a much lighter and cheaper bag could be used than was necessary for the oxy-hydrogen light. It is, however, interesting to us as being a proto-type of a much later invention, Mr. Scott’s saturator, which it resembles in principle, although the division of a stream of oxvgen—the main idea of modern saturators—was not then thought of. The next apparatus so far as my recollection serves, introduced, I think, also by Mr.Pumphrey, vapourised methylated spirit ; it was described in The British Journal Almanac for 1876, by the Rev. Frederick Hardwick, and spoken of very ; highly by him. It was necessary in this vapouriser, as in the last, to burn small lamps under the jet tubes in order to prevent the vapour re-condensing. It will be as well to make clear to you the theory of present-day saturators, and I hope to do so by means of a diagram. | It will be seen ¢ See illustration in November, 1894, issue of this Journal. that the current of oxygen is divided, one stream passing through the vapour in chamber with which the gas is saturated; the other being carried to the mixing chamber of jet; the oxygen, after being saturated with ether, burns like ordinary coal-gas, the addition of pure oxygen is made in the usual way, and a most brilliant light is produced, scarcely if at all inferior to oxy-hydrogen light proper. One of the first, if not the first, saturators brought into practical use, was designed by Mr. Broughton, it was a copper vessel about 12 x 6x 2tinches, which had a series of horizontal partitions so contrived as to cause the stream of oxygen to pass backwards and forwards, zig-zag fashion, over the vapour rising from ether placed in the bottom of apparatus. Messrs. Hardwick & Broughton improved upon this by making the partitions upright. so that the oxygen was practically in contact with ether the whole distance. + j See illustration in January, 1895, issue of this Journal. This saturator was successful in experienced hands, but one or two serious explosions caused the apparatus to be looked upon with distrust. It was suggested at the time that a defect in the partitions allowed the oxygen to make a. short cut, and so, not becoming saturated with ether, an explosive mixture was formed. That the gas was not saturated is certain, but I am not satisfied with the explanation given. Flame extinguishers were always supposed to be used in connection with it; Mr. Hardwick preferred packing the mixing chamber of jet with finely granulated pumice. In the explosions mentioned burning ether was thrown in all directions, and to obviate this, a new form of saturator was devised, consisting of two brass barrels packed with ether saturated flannel, the gas passing through a small wirework tube in the centre ; when properly charged with ether the oxygen is thoroughly saturated and an explosion impossible. A serious explosion was hardly likely in any case, but one or two rather alarming flares were reported. This saturator, which was brought out by Messrs. Cutts & Sutton, § and invented, I think, by Mr. § See illustration in March, 1890, issue of this Journal. Ives, is still used by many lanternists; the secret of success seems to be in the fact that the saturator works best when warmed. The late Mr. Scott, of Cardiff, an enthusiast in these matters, realising that the temperature of the ether materially affected the safety oxyether lighting, invented a saturator with an arrangement for warming the fluid to be vapourised ; he used gasoline by preference.jj It |; See illustration in July, 1892, issue of this Journal. consists of an inner vessel tight’y packed with wool, surrounded by a warm air jacket, heated by a_ small lamp on one side; the oxygen is conducted through a spiral perforated tube, and so becomes saturated with the vapour. I have never heard of an explosion with this apparatus ; it is, L believe, still used by many. In the Oprican Magic Lantern JoURNAL AND PuorocrarHic Enniancer, of May, 1892, appeared a woodcut, aslide of which I now show on the screen, which probably did not receive much admiration from lanternists, and yet this marks the most important period in the improvement of saturators. Up to this date all saturators were intended to be used outside the lantern. Mr. Lawson in his invention now before you, proposed to utilise the heat of the lantern by contriving his saturator with combined jet, so that it could be used inside of the lantern.q 4; See illustration in March, 1893, issue of this Journal.