118 CONTRIBUTIONS TO MINERALOGY. [bull. 262. 
Excepting* for the high-water content the analysis agrees very well 
with the formula. No allowance was made for the small amount of 
andalusite present, which would slightly alter the ratios. 
The analysis by Schimpff of dumortierite from Germany is given 
below. Obviously it is worthless for an} T calculation. 
Si0 2 36. 81 
A1 2 S 57. 27 
CaO 1. 66 
MgO 1. 38 
Ign 1. 31 
B 2 3 strong test 
98. 43 
Of similar character is Jannasch's analysis of the Argentine mineral. 
The sample was .probably very impure. 
Si0 2 35. 01 
B 2 3 2. 51 
Ti0 2 (Ti 2 G 3 ?) 1. 08 
A1 2 3 51. 49 
Fe 2 3 1-04 
CaO 28 
MgO 54 
K 2 3. 62 
Na 2 96 
H 2 3. 02 
99.55 
Specific gravity 3. 255 
There now remain the analyses of Whitfield and Riggs, of which 
but one is suitable for any calculation. The analyses are as follows, 
No. 1 being of the New York mineral, by Riggs; No. 2 of the New 
York, and Nos. 3 and 4 of the Arizona mineral, bv Whitfield. 
Si0 2 . 
Al-A 
MgO. 
Na 2 
PA - 
B 2 3 - 
lgn._ 
34. 82 
55. 30 
.57 
1.04 
1. 76 
4.07 
2.96 
100. 52 
31. 44 
68.91 
trace 
100.33 
31.52 
63. 66 
.52 
.11 
.37 
2.62 
1.34 
100. 14 
27. 99 
64. 49 
trace 
.20 
4. 95 
1.72 
99. 35 
