Hydro-oxygen Bloivpipe. 37 



Art. VI. — On certain Improvements in the Construction and 

 Supply of the Hydro-oxygen Blowpipe, by which Rhodium, 

 Iridium, or the Osmiuret of Iridium, also Platinum in the 

 large way, have been fused; by Robert Hare, M.D., Professor 

 of Chemistry in the University of Pennsylvania. (Commu- 

 nicated by the Author.) 



Having observed while I was a pupil of my predecessor, Dr. 

 Woodhouse, in the year 1801, that a jet of hydrogen when in- 

 flamed in atmospheric air, of which only one-fifth is oxygen, pro- 

 duced a heat of pre-eminent intensity, I was led to infer that in 

 combining with pure oxygen, the gas in question ought to pro- 

 duce a temperature at least five times as great. This led to the 

 contrivance of two modes of producing a jet consisting of a mix- 

 ture of hydrogen with oxygen. Agreeably to one mode, the gase- 



ous currents meeting like the branches of a river, were made 



analogously to form a common stream. This object was accom- 



perf orations 



per 



ration, commencing at the opposite surface, and so extended as 

 to join them at the point of their meeting. The other mode 



was that of causing one tube to be within another, so as to be 

 concentric ; the outer tube being a little the longer of the two, 

 the latter being employed for hydrogen, the former for oxygen. 



In the year 1814, this last mentioned mode was improved, so 

 as to have the means of securing, by adjusting screws, the con- 

 centricity of the tubes, and varying the distance of the orifice of 

 efflux of the inner tube from that of the other. 



The constructions employed in 1801, were described and pub- 

 lished in a pamphlet, and afterwards republished in Til loch's 

 Philosophical Magazine, Vol. xiv, and in Annales de Chimie, 

 Vol. xlv. At the same time an account was given of the fusion 

 of pure lime and magnesia, and of the fusion of platinum. Sub- 

 sequently in a paper published in the Transactions of the Ameri- 

 can Philosophical Society, it was mentioned that I had volatiliz- 

 ed platinum. . , , 



About the year 1811, Professor Silliman, in a memoir read be- 

 fore the Connecticut Academy of Sciences, gave an account ot 

 a series of experiments, in which the experiments which l naa 

 performed were repeated, and many additional fusions maae. l 

 had adverted to the intensity of the light produced during the ex- 

 posure of lime to the flame. Alluding to the heat and light, my 

 words were, " the eyes could not sustain the one, nor t tie most 



^r-_* 'u_. „ -„„;«,♦ ♦ko ^h of » The intensity of the 



substances 

 was still more insisted upon by Silliman 



