354 Mr. L. Thompson oti Antimoniuretted Ht/drogen, 



peculiar and approaches nearly to that of arseniuretted hydro- 

 gen ; inflamed at a jet in the open air it burns with a pale 

 bluish green flame resembling that of arseniuretted hydrogen, 

 and gives off" a dense white volatile vapour, which collects, as 

 a semicrystalline 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 nearest 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 hydrogen under similar cir- 

 cumstances ; and although a practised eye may discern some 

 difference between the crusts, that from antimony being more 

 silvery and metallic, yet the line of demarcation 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 antimonial oxide 

 will become of a darker yellow than the arsenical; but this is 

 also fallacious, for a small quantity of antimony gives a yellow 

 not darker than orpiment, and if any metallic arsenic be pre- 

 sent in the arsenical oxide, a portion of realgar forms and 

 gives the product an orange hue. The ammoniaco-sulphate of 

 copper is liable to similar objections, for a large quantity of 

 the oxide of antimony produces a whitish green precipitate 

 which might easily be mistaken for Scheele's green. The two 

 metals may, however, be distinguished by adding a drop of 

 nitric acid to the crusts; they will immediately dissolve, and on 

 evaporating to dryness a white powder is left in each instance. 

 A few drops of a dilute solution of the nitrate of silver being 

 now added, and the whole exposed to the fumes arising from a 

 stopper moistened with ammonia, the antimonial solution will 

 be observed to deposit a dense white precipitate, whereas that 

 from arsenic will give the well-known Canary-yellow flocculi. 

 I prefer this mode of using silver to the ammoniaco-nitrate of 

 the same metal, for the slightest excess of ammonia destroys 

 the colour, but by watching the effect of the vapour, the exact 

 quantity requisite is easily obtained. 



For the purpose of testing, it is unnecessary to use the alloy 

 which I have mentioned, as the gas arising from one grain of 

 tartar emetic, or any other salt or oxide of antimony, with a 

 little diluted sulphuric acid and zinc, will furnish an abundance 

 of metallic crusts; indeed a single drop of the common wine of 

 antimony will produce a very distinct film. In accordance with 

 the names already given to similarcompounds of hydrogen and 

 the metals, 1 have called this gas antimoniuretted hydrogen. 



