AN INVESTIGATION INTO 
penetrating the augite and even the iron ore, but not the olivine so far as 
can be observed. Many little seams apparently of the nature of joints traverse 
the rock, and care had to be exercised to secure prisms of the rock free from 
these, on which to determine the elastic constants. 
A color-process photograph of a polished surface of the rock is shown in 
Plate XV A, and a photomicrograph of a thin section of the rock taken in ordi- 
nary light and magnified 27 diameters is seen in Plate XV B. 
Four test pieces were used in determining the elastic constants of the rock, 
viz, three round columns and one nearly square prism. They are designated 
as a, b, c, and d. The three round columns were cut out of a block of the 
diabase by means of an annular diamond drill. For these we are indebted 
to Dr. Logan Waller Page, of the Agricultural Department at Washington. 
Two measurements were made on each of these in planes at right angles to 
one another, in each case, while four measurements were made on the prism 
d, using two pairs of faces. In this way ten sets of measurements were made 
for the elastic constants of this diabase. 
The values obtained are given in the following tables : 
Olivine Diabase, Sudbury, Ontario, Canada. 
No 
d 
d 
d 
d 
d 
d 
d 
Size 
1.000 X .864 
1.00 
1.00 
1.00 
Area . . . 
864 
864 
864 
864 
E 
13,150,000 
13,330,000 
13,450,000 
12,860,000 
<r 
276 
.285 
287 
279 
D 
9,810,000 
10,340,000 
10500 000 
9 655 000 
C 
5,170,000 
5,200,000 
5,230,000 
5,020,000 
.... 
.... 
Longitudinal compression (multiply readings by 4 for millionths). 
Lateral extension 
(millionths). 
Load (in 
Side 
Side 
Side 
Side 
Side 
Side 
Side 
pounds). 
U. 
u i 
U* 
U* 
Ui 
tt 
U. 
1,000. . 
O 
O 
O 

O 


2,000. . 
25 
25 
25 
26 
25 
25 
2 5 
3,000.. 
50 
51 
52 
58 
50 
50 
49 
4,OOO. . 
75 
7 6 
80 
85 
75 
75 
74 
5,000. . 
102 
103 
105 
no 
100 
IOO 
98 
6,000. . 
127 
130 
135 
140 
124 
125 
124 
7,000. . 
8,000. . 
155 
I8 5 
155 
I8 7 
152 
182 
169 
195 
148 
J 73 
150 
170 
146 
1 68 
9,000. . 
8,000. . 
220 
190 
2I 7 
190 
215 
185 
225 
200 
200 
175 
198 
194 
168 
7,000. . 
6,000. . 
157 
130 
157 
134 
155 
134 
175 
145 
152 
128 
147 
I2 5 
5,000. . 
105 
105 
105 
no 
103 
99 
4,000. . 
7 6 
- 80 
80 
80 
78 
75 
3,000. . 
50 
54 
50 
51 
52 
5 
2,000. . 
2 5 
27 
25 
25 
28 
2 5 
1,000. . 

3 


O 


