596 ON DETECTING THE 
combustion, we might with propriety have con- 
. cluded that when, on adopting Mr. Marsh’s plan, 
we happened to get a metallic deposit or crust, 
arsenic was present in the matter under examina- 
tion ; but in the number for May, 1837, of the 
London and Edinburgh Philosophical Maga- 
zine, and Journal of Science, Mr. Lewis Thomp- 
son directs our attention to a combination of anti- 
mony with hydrogen, which he calls antimonu- 
retted hydrogen, and points out the near resem- 
blance which it bears to arsenuretted hydrogen. 
This combination is procured under circumstances 
similar to those under which arsenuretted hydro- 
gen is formed; antimony, of course, being sub- 
stituted for arsenic. The smell of antimonuretted 
hydrogen in a great degree resembles that of 
arsenuretted hydrogen; and the two gases are 
much like each other in their general properties, 
as I find in corroboration of Mr. Thompson, who 
says, that when a piece of cold window glass is 
held in the flame of antimonuretted hydrogen, a 
metallic crust is deposited, and when a glass tube 
is used, the metallic film is formed on that part of 
the tube nearest the flame, and the white oxide 
around and above it, which appearances coincide 
im a very remarkable manner with those produced 
by arsenuretted hydrogen under similar circum- 
