418 Mr. Tennant on two Metals , &c. 
If the pure oxide of osmium, dissolved in water, is shaken 
with mercury, it very soon loses its smell ; and the metal, com- 
bining with the mercury, forms a perfect amalgam. 
Much of the mercury may be separated by squeezing it through 
leather, which retains the amalgam of a firmer consistence. The 
remaining mercury being distilled off, a powder is left, of a dark 
gray or blue colour, which is the osmium in its pure state. By 
exposing it to heat with access of air, it evaporates, with the 
usual smell ; but, if the oxidation is carefully prevented, it does 
not seem in any degree volatile. Being subjected to a strong 
white heat, in a cavity made in a piece of charcoal, it was not 
melted, nor did it undergo any apparent alteration. Heated in 
a similar situation with copper and with gold, it melted with 
each of these metals, forming alloys which were quite malleable. 
These compounds were easily dissolved in nitro-muriatic acid, 
and, by distillation, afforded the oxide of osmium with the usual 
properties. 
The pure metal which has been previously heated, does not 
seem to be acted on by acids ; at least I could not perceive 
any effect produced by boiling it for some time with nitro- 
muriatic acid. By heating it in a silver cup with caustic alkali, 
it immediately combined with the alkali, and, with water, gave a 
yellow solution, similar to that from which it was procured. 
Acids expel from this solution the oxide of osmium, which has 
the usual smell, and the power of giving to infusion of galls the 
blue colour before mentioned. 
