Weathering of Diabase in Virginia. — Watson. 
93 
chemical nature and relationship of the same rock in as many 
stages of weathering. 
Recalculating the analyses in columns 1 and III, in each 
of the three tables, on the basis of lOO, and assuming one of 
the constituents as a constant factor, the results given in 
columns VII, VIII and IX are obtained. 
"A." 
Calculated Loss of Material in the Fresh and Partially 
Decomposed Rock. 
Fresh 
Olivine diabase 
Partially 
Decomposed 
Olivine diabase 
Calculated to 
total of 100. 
Calculated amounts 
saved and lost. 
I 
II 
III 
IV 
V 1 VI 
VII 
VIII 
IX 
H 
d 
.1- 
O^JQ 
a— U 
a 
5 
"a 
03 
00 
11' 
< i 

£ 
5 ,: 
u 
3 S 
c > 
a- s 
3 2 
|8 
si 
SiO., .... 
*Ai:o, . 
Fe.ba .. 
CaO .... 
MgO ... 
Na^O. .. 
K^O .... 
HoO .... 
45 
13 
II 
9 
15 
3 
o 
o 
73 
48 
6o 
92 
40 
24 
47 
94 
12.78 
g. 10 
8-75 
4-37 
8.65 
Not jet, 
0.94 
47-87 
14-43 
11.55 
10.45 
10. q8 
3-47 
0.61 
1.82 
Not det. 
10.93 
5-83 
4-49 
4.28 
0.91 
0.45 
1.82 
45-38 
13-38 
11. qi 
9.84 
15.28 
3.21 
0.47 
0-93 
47-49 
14.32 
11.46 
10.37 
10.50 
3-44 
0.61 
1. 81 
0.99 
0.00 
0-79 
0.15 
5-47 
0.00 
0.00 
0.00 
97-81 
100.00 
93-09 
98.47 
64.19 
100.00 
100. oot 
I 00. oof 
2.19 
0.00 
6.91 
1-53 
35-81 
0.00 
0.00 
0.00 
Total ... 
lOO 
78 
44-59 
100.78 
28.71 
100.00 
100.00 
t7-40 
31.81 
The special features to be noticed in this table are: (i), 
The relative amounts of material in the two rocks soluble in 
dilute hydrochloric acid, which are given as 31.81 per cent for 
thefreshrock, and 28.71 percent, for the partially altered; the 
fresh rock yielding, therefore, the largest amount of extract. 
(2), An assumption of almost double the amount of water in 
column III as in column i; and (3), a slight percentage loss 
for the silica, iron and lime, with a rather marked loss in the 
magnesia, amounting to 35.81 per cent, yielding a total loss 
for the entire rock of 7.40 per cent, the alumina being the con- 
*Alumina is talcen as the constant factor in the above calculations. 
tGain. 
|Per cent. 
