ME. MALLET ON THE TEANSIT-VELOCITY OF EAETHQIJAKE WAVES. 667 
Table VIII. — Holyhead-Rock Compression. Experiments H, 
on Soft Quartz ; pressure parallel to lamination. 
No. of 
experiment. 
Pressure due to 
the unit of 
surface 
= 1 square inch. 
Compression 
readings of the 
column of 
0'707 inch. 
Compression 
readings due to 
the successive 
loads. 
Total compressions 
produced by the 
load on column 
of 0707 inch. 
Total compressions 
reduced to a column 
of unit height 
= 1 inch. 
lbs. 
in. 
in. 
in. 
in. 
1. 
50 
•170 
•000 
•000 
•0000 
2. 
1,000 
•144 
•026 
•026 
•0374 
3. 
2,000 
•101 + 
•043 — 
•069 
•0992 
4. 
3,000 
•101 
•000 + 
•069 
•0993 
5. 
4,000 
•100 
•001 
•070 
•1007 
6. 
5,000 
•099 
•001 
•071 
•1021 
7. 
6,000 
•098 
•001 
•072 
•1036 i 
8. 
7,000 
•019 
•049 
•121 
•1741 
9. 
7,000 + 
Crushed before the increased load was applied. 
Note. — The cube H was 0'695 inch on the side, and the necessary reductions have 
been made in column 2 and subsequent ones. 
Table IX. — Holyhead-Rock Compression. Slate Rock. — Results of compression 
compared. Column of unit length = 1 inch. 
No. of 
experiment. 
Pressure in 
pounds on 
unit of surface 
= 1 square inch. 
A. 
Hard slate 
across lamina. 
B. 
Hard slate 
with the lamina. 
E. 
Soft slate 
across lamina. 
F. ! 
Soft slate with 
the lamina. 
lbs. 
in. 
in. 
in. 
in. 1 
1. 
50 
•0000 
•0000 
•0000 
•0000 i 
2. 
1,000 
•0052 
•0130 
•0014 
•0029 1 
3. 
2,000 
•0390 
1 
4. 
3,000 
•0403 
•0029 
5. 
4,000 
•0416 
•0072 
6. 
5,000 
•0091 
•0043 
•0115 
7. 
6,000 
•0129 
•0147 
8. 
7,000 
•0104 
•0468 
•0259 
9. 
8,000 
•0494 
•0389 
10 . 
9,000 
Crushed. 
11. 
10,000 
12 . 
11,000 
•0158 
13. 
12,000 
•0117 
•0187 
14. 
13,000 
•0404 
15. 
14,000 
•0548 
16. 
15,000 
•0520 
Crushed. 
17. 
16,000 
•0533 
18. 
17,000 
•0572 
19. 
18,000 
•0585 
20. 
19,000 
•0130 
21. 
20,000 
22, 
21,000 
23. 
22,000 
24. 
23,000 
•0143 
25, 
24,000 
Crushed. 
•0624 
26. 
25,000 
27. 
26,000 
’ -0650 
28. 
27,000 
•0689 
29. 
28,000 
Crushed. 
30. 
29,000 
in. 
in. 
in. 
in. 
Mean compression for each J 
•0006217 
•0025000 
•0039144 
•0037000 
1000 lbs. on unit of siirfae.p 1 
up to 
up to 
up to 
up to 
23,000 lbs. 
26,000 lbs. 
14,000 lbs. 
7000 lbs. 
