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ON SEISMOLOGICAL INVESTIGATION. a 
6. India: Madras. Director, Dr. C. Micu1e SM1rH. 
Dr. C. H. Michie Smith writes as follows :— 
‘The instrument is placed in the old magnetic room of the Observa- 
tory on one of the old piers. The surrounding ground is mainly a stiff 
clay which cracks during the hot weather, leaving fissures many inches 
deep. The Observatory is on a plain, and is about three miles from the 
sea and 20 feet above sea level. No air tremors were experienced during 
the time under report, but the instrument gave a great deal of trouble 
specially owing to changes in the length of the suspending silk thread, 
caused probably by alterations in the amount of moisture in the air. The 
instrument will be removed to Kodaikanal as soon as a room is ready 
for it.’ 
The Madras Register. 
Shide Prelim. | shock | Maxi- | 3 | Shock | Fina 
No. |"xo Date | Tremors | jocins ime | ae Beat Tremor Remarks 
; begin Deen om | ee ends 
1898 
H. M. Ss. | H. M. 8. | H. M. S.| MM. | H. M.S. | H. M. S. 
1 | 201 May 21?| 17 14 25 | 17 20 1/17 20 1 0°75| 17 26 5 | 17 35 38 _ 
— | 201 —_ — 19 54 0 — 05 | 19 55 O _ — 
2 | 210? — — — — _ _— _ About this time 
a large number 
of small dis- 
turbances, but 
none character- 
istic of a true 
shock—possibly 
theywere caused 
by a spider. 
—j| — | June 4 _ _ a — _~ _ Instrument not 
to working, 
Aug. 11 
3 | 230 | Aug.31 | 20 2 5 | 2012 25 | 2018 0j| 10 | 20 33 35 | 20 43 36 _ 
4} — | Sept. 9 _— > 48 38 _— <0 3 40 47 —_— mc 
5 | 232? 3) LS _ 17 34 25 — — | 17 35 37 — Very slight. 
6 | 233 2 = 12 34 43 = — | 12 39 13 = a 
7) — 3) 28 = 12 24 13 = == (2.31 19 = 4 
8) — Oct. 1 _ 3 27 49 329 1 —_ 3 30 31 _ t 
9 | 235 ? cp alli —_ 17 2 36 _ — | 175912 _— Probably due to 
a thunderstorm. 
10 | 238 ala — $5019] 35225) 1:2 356 40| 4 6 26 | Felt as a shock 
in N. India, 
11| — | Nov.12 _ 947 1 —_ —_ 9 48 31 — Very slight. 
12}; — 3 30 —_— 12 32 30 — _ 12 35 0 — 8 
13 | 240 | Dec. 1 | 12 45 14] 12 52 21/1255 9| 10/13 343] 18 911 — 
14 _— = — 12 631 — _ 12 10 31 _ Very slight. 
15 — joe _ 13 15 31 — — 1319 1 _ py 
1899 
16 — | Jan, 23 _ 2 425 2 449 05 210 25 —_ _ 
17 | 251 » 30 _ 17 48 19 | 17 52 25 | 1°0 L767 +1 — = 
18 — | Feb. 5 — 14 8 29 | 14 18 31 | 3°0 14 52 46 — — 
19 _ oe — 16 41 5 | 16 48 51 | 2°0 16 55 34 — — 
20 _ 6 _— 18 32 36 | 18 37 35 | 15 18 43 47 —_ — 
21 _ AG _— 20 42 15 | 2046 4] 15 20 54 32 _— —_ 
22 —_ ea _ 4 53 29 5 331] 1:0 518 0 _— — 
23); — os we — 20 28 27 | 20 33 7 | 2°5 20 49 27 — Time slightly un- 
certain. 
24 — =e _ 050 1 0 54 31 | 1:0 PO. 4 — — 
25 - » 10 _ 13 36 28 | 13 45 21 | 10 13 46 54 — ? 
Norvss.—After November 12 the period of the oscillation may be taken as 16 secs, Before that time it 
was less, but the exact period is very uncertain aud was variable. 
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