110 
ORIGINAL COMMUNICATIONS. 
conclusions, unless we are acquainted with all the sources 
from which error may arise. The discovery alluded to above 
is a " hitherto unnoticed combination of antimony and hydro- 
gen," which he denominates " antimoniuretted hydrogen." 
This gas was procured by acting upon an alloy of equal parts 
of antimony and zinc with dilute sulphuric acid. It presents 
the following properties: 
" Antimoniuretted hydrogen [Land, and Edin. Phil. 
Mag. May, 1837,) is a colorless inflammable gas, exploding 
violently by the electric spark or lighted taper when mixed 
with an equal volume of oxygen, chlorine, or atmospheric air; 
its odor is peculiar, and approaches nearly to that of arseniu- 
retted hydrogen; inflamed at a jet in the open air, it burns 
with a pale, bluish green flame, resembling that of arseniuret- 
ted hydrogen, and gives off a dense white volatile vapor, 
which collects as a semi-crystalline oxide on cold bodies 
placed over it, affording another instance of the similarity of 
these gases; when a piece of cold glass or china is held in the 
flame, a metallic crust is deposited, and when a tube of glass is 
used, the metallic film is formed on that part of the tube near- 
est the flame, and the white oxide around and above it. It is 
unnecessary to add, that these appearances coincide in a very 
remarkable manner with those produced by arseniuretted hy- 
drogen under similar circumstances, and although a practised 
eye may discern some difference between the crusts, that from 
antimony beingrnore silvery and metallic, yet the line of demar- 
cation is not easily drawn, for a thin film of antimony looks 
more like arsenic than antimony, and a thick crust of arsenic 
has the metallic appearance of antimony. When sulphuretted 
hydrogen is passed over the oxides of these metals, the anti- 
monial oxide will become of a darker yellow than the arseni- 
cal; but this is also fallacious, for a small quantity of antimony 
gives a yellow tint not darker than orpiment, and if any me- 
tallic arsenic be present in the arsenical oxide, a portion of 
realgar forms and gives the product an orange hue. The am- 
moniaco-sulphate of copper is liable to similar objections; for 
