316 SS. L. Penfield—Chemical Composition of Childrenite. 
from the — and oxide of iron with which they were asso- 
ciated. lustrous crystals were accepted, and any doubt- 
ful carte was discarded. Between eight and nine tenths of 
a gram were thus obtained. Analysis I is a complete analysis 
made on a little over half a gram; it was conducted with the 
greatest care and a special test was made for alkalies, so = 
they might be determined quantitatively if present. As 
in his analysis found iron sesquioxide present, the veceniad 
three tenths of a gram of the mineral were tested quantitatively 
with potassium permanganate; the result indicated 26°08 per 
tion was secacs and a ALO, and FeO determined in it 
gravimetrically (analysis TD) as a control on the other analysis. 
Ratio calculated 
: I. from analysis I. 
FO 80°19 29°98 "212 1. 
AiO, 21°17 21°44 208 98 
FeO 26°54 26°20 368 
MnO 4°87 069 } *458 2°16 
CaO P21 “021 
H,O 15°87 “882 4°16 
Quartz 10 
99°95 
The anaes ratio corresponds <i to the following: 
RO: H,O=1:1:2:4(R==Fe, Mn, and Ca), 
4 he the empirical formula R, AL »P,0,,, 4H,0, which may be 
10) 
Al ipo aioe or AN’ o b+ + ston: { +4aq, 
or the same as that made out for eosphorite 
e formula in this case corresponds to the following percen- 
tage composition: P,O, 30°80, Al,O, 22°31, FeO 26°37, MnO 4°87 
H, ,0 15°65=100. This agrees satisfactorily with analysis 1. 
Note on the erm between Childrenite and Lea EB: ; by 
GrEorGE J. BrusH and E. 8. D 
In our former paper, to which Mr. Penfield refers, we showed 
that childrenite and eosphorite were crystallographically close’y 
homceomorphous. Thus the axial ratios for the two species 
a 
b (macro- a ( i 
; diagonal.). diagon 
Childrenite, Tavistock (Cooke) o oor 1°294 1-000 
Eosphorite, Branchville 1-287 1-000 
