232 J. P. Cooke on Stibiotrizincyle and Stibiobizincyle. 
When the alloys of zinc and antimony are treated with strong 
acids, hydrochloric or sulphuric, they are as a general rule, and 
under favorable circumstances, completely deomposed, the zine 
uniting with the acid and the greater part of the antimony sepa- 
ing as a black powder, only a very small amount ever, even un- 
der the most favorable circumstances, escapes as antimonuretted 
hydrogen. When the alloys are in granules it is almost invaria- 
bly the case with those which contain more than 50 per cent. of 
antimony that after a short time the acid ceases to act, owing to 
the formation of a coating of antimony on the surface. ‘The ac- 
tion is of course renewed on reducing the alloy to powder, but 
here as in other alloys, the less oxydizable metal appears to be 
able to protect entirely a certain amount of the other from the 
action of acids. ‘ 
These facts in connection with those previously stated int 
ard to the increased action of the alloys on water in presence 0 
platinum sufficiently explain the remarkably rapid decomposition 
of water obtained by means of alloys which have been previou 
ly acted upon by hydrochloric or sulphuric acids, even after the 
excess of acid and the salts formed have been completely te 
moved by repeated washings. This decomposition is so rapid 
that I have obtained from 200 grammes of an alloy containing 58 
er cent. of antimony prepared as just described and boiled with 
water, nearly a litre of gas in ten minutes. It is plain that the 
antimony acts here exactly as the platinum in the previous e© 
periments by forming a galvanic circuit with the alloy. A set © 
experiments was made with alloys which had been acted upo? 
by acids similar to those the results of which are given 0 the 
table. The irregularities however which resulted from the une- 
qual action of the acids on the different alloys, from the differen- 
j Tey 
were always much greater than those obtained by using plat 
num, with the exception of pure zinc, whose decomposing pow 
was not increased by the action of acids. 
This new mode.of decomposing water is of value as a proce 
for preparing pure hydrogen, and also for illustrating the compe 
h im 
is 
er 
a) 
s 
°“S 
hydrogen obtained is chemically pure. : If commercial antimon 
and zinc are used, the gas will be found contaminate : 
small amount of arseniuretted hydrogen, so small howe 
be with difficulty detected, and entirely inappreciable in the 
refined eudiometric experiments. wine 
Gas evolved from an alloy containing 50 per cent. of com fole 
cial antimony was burnt in Regnault’s endiometer with the 
lowing results : 
yer as t0 
