222 J. B. Pearse on Minerals of the Chlorite Group. 
In no case was any crystal chosen the color of which was im 
tinct. eh 
The following is an outline of the method of analysis adopted. 
After solution by means of carbonate of soda, and chlorhydrie 
acid, the usual precautions being taken for an accurate estima: 
tion of the silica, the filtrate was rendered slightly alkaline with 
ammonia which precipitated the sequioxyds of iron, chrome and 
nickel oxyd from the sesquioxyds; the latter was then dried, 
weighed, pulverized carefully with carbonate of soda, and then — 
nitric acid, was treated by sulphid of potassium, as al 
separate: the nickel from the lime and magnesia. The lime Wis _ 
ecipitated as oxalate, and estimated as sulphate; the magnesia — 
in the usual way. After the solution of th 
estimation of the oxyd of nickel, the oxyd was redissolved, and : 
separated by ammonia from the impurities which cling oma ; 
lowing results—two determinatious bein g generally made of each - 
Green. ‘. Reddish-green, 
No. 1. No. 2. Average. || No. 1. No, 2. 
Si0,*| 28800 28444 28-699 || 31515 82-200 
Al,0, 18:375 18-375 || 13-74 see 
PaO | 810 ‘370 || +231 200 
303 1-278 Te 
Mg,0| 31-766 32483 32-195 || 34871 34-929 
H,O | 13900 14185 14-095 || 13-933 14-033 
* Si=28-4,0=—16. ag 
_ The joint weight of sesquioxyds in the green was 40°™% we 
4°89 ; that of their separate determinations 24°82, the ann pele 
firming the former, after exclusion of silica. These 2M a 
show that the red and reddish-green are identical, but ere ao 
differ from the green. Since there is one per cent more . mi se : 
* Chem. News, vol. vi, p- 82. 2 al 
