32 CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. [bull.ic 
The reduced analyses and their comparison with the calculated con 
position is as follows : 
Si0 3 . 34. 10 
B,0, 9-98 
A1 3 3 J 32.37 
FeO ! 17-33 
Found. 
Stony 
Point. 
Found. 
Brazil. 
CaO 
Na 2 
H 2 0. 
.52 
2.22 
3.48 
34.26 
9.54 
32.54 
17. 45 
.33 
2.40 
3.48 
Calcu- 
lated. 
A 13 B 2 C 9 . 
34.27 
9.69 
32.36 
17.14 
.45 
2.22 
3.57 
Found. 
Auburn 
100. 00 100. 00 
100. 00 
34.75 
9.56 
33.73 
15.99 
.15 
2.23 
3.59 
Calcu- 
i lated. 
A35B2C27 
34.48 
10.06 
33.28 
15.95 
.17 
2.50 
3.56 
Found. 
Paris. 
100.00 I 100.00 
34.70 
8.94 
34.82 
15.30 
.25 
2.33 
3.66 
Calculated. 
AjoBjCy. 
34.62 
10. 10 
33.60 
15.23 
.27 
2.67 
3.51 
100.130 100.00 
Here again the agreements between analysis and theory are as clo 
as could be reasonably expected. The same thing is true of the bla 
tourmalines from Haddam Neck, Connecticut, and Nantic Gulf. Usn 
letters to represent the several molecules, as above, the Haddam mi 
eral is sharply represented by A 4 B 1 D 2 , and that from Nantic Gull 
AuB-jOsEj. Here is the comparison : 
1 
Haddam Neck. 
Nantic Gulf. 
Found. 
Reduced. 
Calculated. 
1 
Found. 
Reduced. 
33.34 
9.86 
1 29. 01 
] 20. 46 
2.19 
\ 1.74 
3.40 
Calculated. 
SiO a 
B,0: { 
TiO 
34.95 
9. 92 
.57 
31.11 
.50 
11.87 
.09 
4.45 
.81 
2.22 
.24 
3.62 
"33. 78 
9.60 
► 30. 74 
1 19. 31 
.78 
) 2.30 
3.49 
33.67 
9.82 
30.67 
19. 24 
.75 
2.48 
3.37 
35.34 
10.45 
.40 
30.49 
33.60 
9.80 
A1,0, 
Fe.O, 
FeO 
28.84 
8.22 
trace 
7.76 
2.32 
1.76 
.15 
3. 60 
20.55 
MnO 
MffO 
CaO 
2.15 
Na 2 
K ,0 
1.70 
H 2 
3. 36 
100. 35 
100. 00 
100. 00 
1 
100. 49 
1 
100. 00 
100. 00 
To the lithia tourmalines, as analyzed by Biggs, a similar set 
formulae apply, although the comparison between fact and theory is 
quite so close as in the preceding cases. The red tourmalines fi 
Brazil and from Rumford, Maine, are very nearly represented by 
expression nnlTr A1 o/tr 
Al 5 (Si04)r,(BO>), . BOR'H . Al a R'H 2 ; 
