ON SEISMOLOGICAL INVESTIGATIONS. 1] 
* discontinuity ’; and have inferred surfaces of discontinuity within the 
earth to account for it. The view taken in the last Report is that PX is 
not P; that the true P may be recorded alongside PX, but that as P 
tends to become faint after \=90°, PX is read as P by mistake. By 
A=121°-125° P has become so faint as only to be read very rarely even, 
on Galitzin machines (and only twice on W as above). Galitzin machines 
mistake PX for Pat times. We have 
Other Records of Galitzin Machines. 
A A | 
° ° s. Ss. | ° ° s. s. 8. s. 
96-100 | +75 +220 | 111-115 +68 +114 +195 +257 
101-105 +-169 116-120 +61 +200 +274 +-297 
106-110 +77 +256 i 121-125 +51 +-60 +199 
The discussion of the tables for both P and 8 beyond 90° thus involves 
special difficulties and is deferred to the next Report. Meantime the 
following table gives the best values for P and 8 that can be got from the 
above discussion, as applicable to G machines. In deriving them the W 
machines have of course also been used, with the above constant correc- 
tions. Further a little ‘smoothing’ has been used, and the values of 
S and P compared and slightly modified so that the ratio of 8 to P may 
vary continuously ; the change appears indeed to be sensibly linear. 
The tenths of seconds are inserted merely to make the tables smooth ; 
in deriving the corrections, the means of five consecutive figures in the 
adopted tables have been taken. 
TaBieE II. 
Suggested Corrections to Adopted Tables for G Machines only. 
AE 
J ee See a erst Ui cie itt 2 New | New | Ratio 
eer bris Bk, | Be le SP P 8 
° Ss. S. Ss. Ss. Ss. 
8 + 24 EG ia! L735 123-4 2153 1:745 
| 13 + 03 7/67] — 8:0 1925 | 335°7 1-749 
| 18 a 22 — 56 — 7-8 259°0 454:0 1753 
be 22 + 0°4 = aie — 83 3166 5563 1757 
} 28 hae —13°3 —11'5 366:2 645°3 1:762 
= 33 — 53 —18°7 —13:4 4105 | 724:9 1°766 
38 — 65 —18°8 —12'3 451°7 799-4 1770 
43 — 65 —15°8 — 93 491°7 872°4 1-774 
48 — $2 —10°4 iPS 530-4 943-2 1:778 
oe 53 Se en eee — 59 567-4 1011°5 1:782 
| 58 ++ 4-1 1:3 — 54 602-9 1077°3 1786 
+63 + 4:4 — 09 — 5:3 636°2 1139-7 1792 
m- 68 + 3:9 = Oe =| 62 668-1 1199-5 1:796 
| 73 + 9-2 LDS Sys 698-0 1256:7 1:800 
78 — 02 — 89 =e 7268 1311°3 1-804 
88 SL —13-0 —10°9 7541 1364-0 1-808 
88 — 43 —17°4 —13°1 780°3 1414-6 1-813 
fe 98 — 66 —21-1 —14°5 805°6 1464-1 1818 
| 98 = 95 23-6 141 830°3 1512-4 1-822 
| 103 —10°3 —23°5 —13°2 8545 1560°3 1-826 
108 —10-2 —22°8 —12°6 878°0 1607-2 1-831 
ee) ae GT 901°6 1654°5 1°835 
=e 
—e 
mw 
el 
| BOS 
om 
lea 
i 
neo 
oO 
| 
i 
oO 
o 
bo 
i 
~I 
—_ 
~1 
oS 
oS 
wo 
(or 
ao 
oe 
Oo 
| 
1 
' 
| 
| 
/ 
