ET, Te ete 
Fusion of Iridium and Rhodium. 367 
Stance there was a perfect coincidence in the results obtained, 
21°83 being the numbers’ found by both of these gentlemen. 
Agreeably to another trial made by Dr. Boyé, using river water 
instead of distilled, the number was 21-78, water being in either 
case about “sixty-eight with allowance for the difference of the 
water, and the temperature being above the standard of 60°, The 
Specific gravity of the specimen, may then be estimated at 21-80. 
_ The specific gravity of fused platinum, purified according to 
_ the instructions of Berzelius, before subjection to the hammer, 
proved in one specimen to be not more than 19-70, although by 
hammering it became equal to 21:23. It is with fused platinum 
that fused iridium should be compared. Of course the specific 
gravity of the last mentioned metal when both are obtained by 
fusion, may be assumed to be one tenth greater than that of the 
former. Moreover as this metal is the only impurity existing in 
the standard platinum of London, of Paris, or of St. Petersburg, it 
follows that a high specific gravity is not to be viewed as a proof 
of purity. Accordingly a ‘specimen of platinum, purified from 
indium by the Berzelian process and which had proved eminently 
Susceptible of being beaten into leaf, was found only to be of the 
gravity of 21-16, while that of a specimen of standard RuSsian 
atinum, very brilliantly white, but inferior in malleability pre- 
sented to me by his Excellency Count Cancrine, as a specimen of 
the purest platinum of the Russian mint, was 21°31. 
_ Of rhodium, I have fused two specimens, one of five penny 
Weights, purchased of Messrs. Johnson & Cocke, the other re- 
ceived through the same channel as the specimen of iridium 
above mentioned*. Rhodium is at least as fusible as iridium, both 
of the specimens alluded to, having been converted into fluid 
globules, That procured from Johnson & Cocke, gave a glolf 
ule Weighing ninety grains. Onasecond fusion, it formed a per- 
fect globule as fluid as mercury; and yet in congealing lost sd 
brillianey by becoming studded with crystalline facets all over its 
Surface, excepting the portion in contact with the support. The 
facets had the appearance of incipient spangles. The rapidity 
with which they were formed seemed to be anomalous. The 
mass being split by a cold chisel and viewed by a microscope, 1t 
ns ~* One other larger specimen from the same source has been fused since the above 
Was Written. % i SS : . : 
