mineral species independent of Phenomena of Isomorphism. 197 
to be equal to the basal angle of the perfect crystals, at least as 
nearly as could be measured. ‘These scales continue up to the 
alloy of 41°8 per cent of zinc, becoming, however, less abundant 
and less distinct. Several specimens of them were analyzed ; 
but no regularity could be detected in their composition, except 
that they all contained a much larger amount of zinc than the 
alloys in which they were formed. 
rystals of Sb Zn? containing an excess of antimony were 
readily obtained from alloys containing less than 27 per cent of 
zinc ey became more and more imperfect as the excess of 
antimony increased, and finally faded out altogether in the alloys 
below 20 per cent of zine. It is evident, therefore, that definite 
and perfect crystals of Sb Zn? can be obtained with a large ex- 
cess either of zinc or antimony above the theoretical composi- 
tion. It is also evident that, of the two compounds, Sb Zn? is 
the most stable,—first, because it is formed to the ‘exclusion of 
Sb Zn? in all alloys containing less zine than the amount _corre- 
sponding to the typical composition of the last compound; and 
Secondly, because the crystals retain the typical composition un- 
der quite a wide variation (viz. between 81:5 and 27 per cent) 
in the composition of the alloy. 
The facts above stated are fully illustrated by the following 
able, which gives the results of a large number of analyses of 
crystals of both compounds formed in alloys containing different 
Proportions of the two metals :— 
Analyses of the Crystals formed in the Alloys of Zinc and Antimony. 
nse cea ssdosvnrise otnre oer Onn ret nr rerun 
Stibiotrizincyle, Stibiobizincyle, 
Composition of the jelous of the oryeud iti ition of the crystals 
alloys byaynthesis a ne eran cache Dine ae pola ee anulysis. ni 
Pr cent Per cent Per cent Pe me et 
fas | ot Sh" | oh Bae ak Se] Sum (Seat | Tob She of Zor | at Sb | Sm 
7040} 2960 | 6415| 3577 | 99-92] 39-00 | 67-00 | 85°37 | 6457 | 99°04 
$650 | $350 | 61-00 | 39-00 |#10000] 33:00 | 67°00 | 35-40 | 64°60 | +100°00 
$450 | 85:50 | 53°50 | 4144 | 99-94 | 8250 | 67°50 | 3462 | 6492 | 9954 
‘ +++. | 55°49) 44:42 91 | 32:50 | 67°50 | 84°61 | 65°39 | ¢100°00 
960 | 8940 | 55-00 | 4509 | 100-09 | 31°50 | 68°50 | 38°95 | 6609 | 10004 
5860| 41-40 | 50:39 | 49:29 | 99-68] 2950 | 70°50 | 8862 | 66°38 | +100-00 
860) 4840 | 49-92 | 5005 | 99-07 | 29°50 | 70°50 | 83°62 | 6638 |71 
470 | 45:30 | 48-26 | 5142 | 9968] 27°50 | 72°50 | 33°85 | 65°81 | 9966 
8270) 47-30 | 4747! 59-58 +100-00 | 26°50 | 73°50 | 82:08 | 6760 | 99°68 
il ius | saan | asia |atn| 23 | ae | Soe | soe | 8 
49°30 | 46°89 | 53 .100-00 | 25°50 | 74°50 | 30°43 
ee 49-30 | 46°45 ri paw 25:00 | 75°00 | 29°88 79°20 | 10008 
no 5180 | 48-66! 51-34 |F100-00 | 2450 | 76°50 | 2876 | 71-24 100:00 
ine | 53°80 | 46°77 | 53-23 |}10000] 23°50 | 76°50 | 2793 | 7185 | 9978 
a 5520 | 44-26| 55°73 |F100:00] 22°50 | 77°50 | 2662 | 73:27 | 9989 
toe. | 5820 | 44°04) 55.96 |f100:00| 21°50 | 78°50 | 2488 | 7474 | 9957 
t0| 8820 | 43:15 | 56-98 | 10008] 2012 | 79°88 | 20°58 | 7942 | 100-00 
iy 58:20 | 4306 | 565 9° 
£80! 58:20 | 42.83! 57-24 | 10007 L 
* In this analysis the antimony only was determined. 
+ In this analysis the zine only was determined. 
