230 J. P. Cooke on Stibiotrizincyle and Stibiobizincyle. 
grammes of each alloy were boiled with pure water, the gas col- 
lected over water, and the number of centimetres cubes evolved 
in an observed time read off after the gas had been cooled to 20° 
. These amounts were afterwards reduced for ten minutes, and 
thus reduced are given in the table. As it was impossible to ob- 
tain the granules of a uniform size in all the alloys, another set 
of experiments was made in precisely a similar way except that 
the alloys were cast into small cylinders of a uniform size. As 
these cylinders had absolutely the same diameter, and almost the 
same specific gravity throughout, the same amount of surface was 
obtained by weighing out 200 grammes of each alloy, and taking 
care to have the same number of little cylinders in each lot. 
Column 3 gives the results of these experiments, where of course 
the same correction for impurities in the antimony must be made 
in the composition of the alloys. It will be seen that the two 
ts of numbers compare as closely as could be expected, it being 
remembered that the amount of surface in the first set of experl- 
ments was variable, while that in the second was constant and 
smaller than the first. These results however must be regarded 
only as approximations to the truth. The limits of variation m 
different experiments on the same alloy would quite cover the 
differences between the first ten numbers of column one, except 
ing the first, so difficult is it to granulate the alloys toa uniform 
size, and submit them during the experiments to precisely similar 
conditions. The numbers of column 3 from which the varie 
tions due to difference of surface have been eliminated, are prob 
ably relatively to each other very nearly correct. 
Table of the Amounts of Hydrogen Gas evolved by 200 grammes of different oe 
of Sb and Zn, in ten minutes, at 100° C. measured at about 20° C. 





; Per Cent. of Sb. 1. 2. 3. 
0 2 63 
ee 5 6 84 
| 10 4 28 3 
15 4 
20 6 18 6 
25 4 19 
| 30 4 f 31 5 
35 5 49 
40 6 72 7 
45 | 5 45 
50 8 44 9 
55 17 46 
58 130 244 84 
60 50 | 139 47 
65 14 35 
70 10 45 7 
15 6 36 
80 5 23 e 

