remaining after the Solution of Platina. \67 



The oxide of osmium becomes of a dark colour with 

 alcohol, and, after some time, separates in the form of black, 

 films, leaving the alcohol without colour. The same effect 

 is produced by ether, and much more quickly. 



This oxide appears to part with its oxygen to all the metals, 

 excepting gold and platina. Silver being kept in a solution 

 of it for some time, acquires a black colour j but does not 

 entirely deprive it of smell. Copper, tin, zinc, and phos- 

 phorus, quickly produce a black or gray powder, and 

 deprive the solution of all smell and of the power of turning, 

 galls of a blue colour. This black powder, which consists of 

 the osmium in a metallic state, and the oxide of the nietal 

 employed to precipitate it, may be dissolved in nitro- 

 muriatic acid, and then becomes blue with infusion of 

 galls. 



If the pure oxide of osmium, dissolved in water, is shakea 

 with mercury, it very soon loses its smell; and the metal, 

 combining 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 con- 

 sistence. 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 oxida- 

 tion is carefully prevented, it does not seem in any degree 

 volatile. Being subjected to a strong white heat, in a cavi- 

 ty 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 1 could not per- 

 ceive 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, oave 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 civing to infusion of galls the blue colour before men- 

 tioned. 



1. 4 XXX. On 



