Hydro-Oxygen Bloisopij^e for the Fusion of Platinum. 357 



Although small lumps of platinum had been fused by many 

 operators with the hydro-oxygen blowpipe as well as myself, 

 it had not, up to the year 1837) been found sufficiently com- 

 petent to enable artists to resort to this process. I am in- 

 formed by Mr. Saxton, that some efforts which were made 

 while he was in London were so little successful, that the pro- 

 ject was abandoned. There was an impression that the metal 

 was rendered less malleable when fused upon charcoal, as in 

 the experiments alluded to. This is contradicted by my ex- 

 periments, agreeably to which fused platinum is as malleable 

 as the best specimens obtained by the Wollaston process, 

 and is less liable to flake. Dr. Ure, on seeing specimens of 

 platinum which I had elaborated and fused in the form of wire, 

 of leaf, ingots and plate, said that there was no one in Europe 

 who could fuse platinum in such masses. He also informed 

 me that it had been found so difficult to weld platinum, that 

 no resort was had to that process. In this I concur, having 

 had the welding tried by a skilful smith, both with a forge 

 heat, and with a heat given by the hydro-oxygen blowpipe. 

 An incorporation of two ingots was effected on their being 

 hammered together, when heated nearly to fusion ; but on 

 hammering the resulting mass cold, a separation took place 

 along the joint by which the ingots were united. 



The difficulty seems to arise from the rapidity with which 

 the platinum becomes refrigerated. It seems to have a less 

 capacity for heat than iron ; and, not burning in the air as 

 iron does, has not the benefit of the heat acquired by iron 

 from its own combustion with atmospheric oxygen. 



Lately, by means of the instrument and process which it is 

 my object here to describe, I have been enabled to obtain 

 malleable platinum directly from the ore, by the continued 

 application of the flame. From some specimens of platinum 

 I have procured as much as ninety per cent, of malleable 

 metal. The malleability is not inferior to that of the best 

 specimens obtained by reducing it to the state of sponge, 

 through the agency of aqua regia and sal-ammoniac. There 

 is however a greater liability to tarnish, arising probably from 

 the presence of a minute portion of palladium. 



Of the fusion of iridium and rhodium, I have already given 

 an account in the Bulletin of the American Philosophical 

 Society, which was subsequently embodied in an article in 

 this Journal for August 1847. 



It remains now to give an account of the apparatus employed 

 in the fusion of platina on a large scale. 



Fig. 1 represents the association of fifteen jet-pipes of plati- 

 num with one large pipe B D at their upper ends, so that 



