mineral species independent of the Phenomena of Isomorphism. 413 
Specific Gravities of Crystals formed in the Alloys of Zine and 
Antimony. 
Composition of the Composition of the 
alloys. crystals. Spec. grav.|Mean spec, . 
of crystals| gray. of |Expansion 
by experi- | zinc and |in crystal- 
Per cent. | Percent | Percent. | Per cent. ment. | antimony.| lizing. 
of Zn. of Sb. of Zn. of Sb. 
AMD AS esaan be dowsesme kh ocdesaen 7153 7153 0-000 
*96-00 BOM Oh Senses || ce ee 7:069 7133 0:064 
*86:20 13°80 |... A alateere's 6°898 7:082 0°184 
+7630 DS ZO ai esd A|neesaete 6-769 7032 0:2638 
70°40 29°60 64:20 35°80 6-699 6°975 0-276 
66°50 33°50 61-00 39-00 6-628 6-959 0°331 
64:50 35°50 58:56 41-44 6:596 6:948 0°352 
62°50 37:50 55°53 44-47 6-506 6-933 0427 
60°60 39°40 55-06 45:00 6440 6:931 0-491 
| 58°60 41:40 50:39 49°61 6396 6-909 0513 
56°60 43°40 49°95 50°05 6'388 6:906 0518 
48-70 51:30 48-66 51:34 6°404 6-900 0:496 
46-70 53°30 46°77 53°23 6376 6:891 0-515 
*10-00 DO00 a Hesecwol tthe ees 6-603 6°721 0-118 
*5-00 95:00 ae ON EA 6655 6-698 0:043 
SEK . | 100:00 eee Acptc: 6°677 6677 0-000 
* Alloys not crystallized. 
+ Point of typical composition of Sb Zn’. 
+ Point of typical composition of Sb Zn?. 
The point of typical composition in the case of the crystals of 
Sb Zn was still further marked in a most decided manner by a 
very remarkable property. It has already been stated that this 
compound has the power of decomposing water with rapidity at 
160° C.; but this is true only of those crystals which have ap- 
proximately the theoretical composition. During the course of 
my investigation I determined the quantity of hydrogen evolved 
by alloys of different composition during a given time, taking 
care, of course, that the circumstances should be the same in all 
cases ; and I found that with the alloy containing 433 per cent. of 
zinc, there is an immense maximum, confined at most between 2 
per cent, on cither side, the alloy of 43 per cent. yielding over 
