The Optical Magic Lantern Journal (April 1895)

68 Now we will go to the “ Universal Dissolving Carrier,” manufactured by the renowned firm of Messrs. John Ottway & Son, of Islington, H.C. The carrier is such that if one slide be focussed, all others afterwards are instantly done so when sent home. It can be used horizontally and vertically, taking framed and unframed slides, I1t delivers the slides at the same time as put in. One of the last carriers to be described is another manufactured by Mr. R. R. Beard, called “Anti halo Self-Centring Shutter Carrier.” It is exactly the same as the selfcentring before described, with the addition of a metal blind or screen that automatically closes and opens the aperture in the carrier. On removing and inserting the slides it works at the same time as the runner that carries the slides. All these carriers can be had of all opticians. — 0 :— The Birth of the Limelight.— No. II. By W. H. Harrison. In my last it was set forth how, in 1801, Dr. Robert Hare, of Philadelphia, invented the oxy-hydrogen blow-pipe, in the form of a mixed jet, in which the two gases mixed inside a small silver nipple. The perforations inside the nipple were Y-shaped; the gases mixed -at the central junction, and came out mixed at the bottom of the leg of the Y. A curious personage now appears upon the ‘scene, one ‘‘ Edward Daniel Clarke, LL.D., Professor of Mineralogy in the University of ‘Cambridge, and Member of the Royal Academy of Sciences at Berlin.’ A long biography of him was published in ‘The Dictionary of National Biography, 1887,” vol. x., edited by Leslie Stephen, and published by Smith, Elder & Co., London, page 421. in Sussex ; his father was a Clerk in Holy Orders. After being instructed by a clergyman at Uckfield, Clarke was sent in 1779 to Tonbridge Grammar School, and about Easter, 1786, he entered Jesus College, Cambridge, as Chapel Clerk. He studied, among other things, natural science, and once acquired local fame by sending up a kitten tied to a balloon. In 1790 he became tutor to the Hon. Henry Tufton, and in July, 1792, he went to Italy as -a companion to Lord Berwick. From 1794 to .1796 he was tutor in the family of Sir Roger He was born | June dth, 1769, at the Vicarage of Willingdon, The Optical Magic Lantern Journal and Photographic Enlarger. Mostyn, and afterwards in the family of Lord Uxbridge ; later on he travelled largely in the Old World as tutor to a rich young man, Mr. John Marten Cripps, in company with William Otter, afterwards Bishop of Chichester, Clarke’s life-long friend and biographer. He brought home Greek statues from Athens, and presented them to Cambridge University. In the biography edited by Stephen occurs the following passage :—‘ About 1816 Clarke, who had been accustomed to submit many of his minerals to the action of the common blowpipe, fell in with the Lssai d'un art de fusion a aide de lair du feu, by M. Ehrman, suivi des mémorres de M. Lavoisier, Strasburg, 1787, in which is described the use of oxygen and hydrogen gases propelled from different reservoirs in the fusion of mineral substances, and in aid of the common blow-pipe. While occupied with this treatise he ‘saw accidentally at Mr. Newman’s, in Lisle Street, Leicester Square, a vessel invented by Mr. Brooke, for a ditferent purpose’ (cf. Brooke’s account of it in Thomson's Annals of Philos. May, 1816, p. 367). He set Newman to work upon it with his ideas, and the latter at last produced the gas (or oxy-hydrogen) blow-pipe.”” That is to say, fifteen years after it had been invented by Iare. The biography edited by Stephen goes on to say: ‘‘ Clarke subjectedsome refractory minerals to the action of his instrument, but at last the copper reservoir burst. He then employed the safety cylinder invented by Professor Cumming, and successfuliy contintied his experiments, the results of which he from time to time communicated in the Journal of the Royal Institution and in Dr. Thomson's Annals of Philosophy. The writer of the biography in Stephen’s dictionary was Warwick Wroth. He makes no mention of Hare. If M. Ehrman, in 1787, invented a Oxyhydrogen blow-pipe, it is clear that Clarke, as well as Hare, was not the first to do so; but from the words ‘‘in aid of the common blowpipe,” I suspect the sentence to mean that when using the common blow-pipe Ehrman directed Streams of oxygen and hydrogen upon the glowing substance, but there was no mixed jet. I will try to find the original documents about: this hereafter. Clarke set forth his claims to be the inventor, in a little book entitled “The Gas Blowpipe,” published in 1819, by T. Cadell and W. Davies, London. Dr. J. Reynolds, the President of the Brixton Camera Club, has a copy. The apparatus consisted of a bladder filled with mixed ' oxygen and hydrogen gases in the proportion to