OP ZINC AND ANTIMONY. 343 



soon, however, disproved, by the fact that an alloy of the same composition, which had 

 not been acted on by acids, when placed in boiling water, produced the same action, 

 though in a less degree, and by the no less important fact, that the rapid evolution of 

 gas could only be produced with alloys containing about 43 per cent of zinc* Two 

 hundred grammes of this alloy granulated to about the size of fine shot evolved one 

 hundred and thirty centimetres of cubes of gas in ten minutes. When previously 

 treated with a few drops of a solution of bichloride of platinum, and afterwards washed, 

 the amount of gas was nearly doubled. The same quantity of alloy which had been 

 previously treated Avith hydrochloric acid, and then thoroughly washed, gave, when 

 boiled with water, nearly a litre of gas in the same time. The gas evolved was pure 

 hydrogen, as is shown by the following experiments. 



1st. The gas evolved from an alloy containing 50 per cent of zinc, which had 

 been previously treated with hydrochloric acid, and then washed, was burnt in Eeg- 

 nault's eudiometer, with the following results : — 



Tension of gas, 0.379 metres. 



" " gas + oxygen, 1.219 " 



" " oxygen after combustion, .... 0.653 " 



" " gas consumed, ...... 0.565 " 



0.566 X I = 0.378, tension of hydrogen consumed. 



2d. Gas evolved from water and alloy at 100° C, but not in ebullition, was passed 

 through hot concentrated nitric acid for six hours, about tAvo bubbles passing a second. 

 The acid, afterwards evaporated to dryness, and the residue dissolved in hydrochlo- 

 ric acid, diluted and treated with sulphuretted hydrogen, gave no indication of anti- 

 mony. 



3d. The gas evolved during violent ebullition gave, under the same treatment, a trace 

 of antimony, which was evidently carried over by the stream in mechanical suspension. 

 Both experiments were repeated twice, with the same results. 



4th. The gas from an alloy of commercial metals, passed for several hours through a 

 small tube of Bohemian glass heated to redness, gave a slight mirror of arsenic. 



5th. The gas from an alloy of pure metals gave no metallic mirror under precisely 

 the same circumstances as in the last experiment. 



From all these results, indicating, as they do, an analogy between SbZnj and the 



• See Table on subsequent page of tbis memoir. 



