ON SEISMOLOGICAL INVESTIGATION. 217 
« The value of one division of the level may be taken=1''0. 
The changes of level N. and 8. were observed. 
2. The crowd collected at 12.15-12.20: 76 men in all. Four com- 
panies of 18 each (with commanders=19) were formed by Mr. G. C. 
Bourne. These were halted with front rank 90 feet from observatory. 
Pos. I.) 
Then marched up, two rear companies taken over fence and brought up 
inside : front rank 5 feet from N. side of building=10 feet from slab. 
(Pos. IT.) 
Then retired to 90 feet. (Pos. ITI.) 
Then marched up again ‘closer’ ; the two front companies came close 
up to building ; front rank thus about 5 feet from slab : other ranks say 
7, 9, and 11 feet from slab. (Pos. IV.) 
Then away again. (Pos. V.) 
Then marched up in open order, viz.: Each man two arm’s lengths 
away : say at 5 feet apart. Front rank still close to hut, ¢.e. 5 feet from 
slab; 2nd rank, 10 feet ; 3rd, 15 feet ; 4th, 20, &c., to Sth, at 40 feet 
from slab. (Pos. VI.) 
Then away again. (Pos. VI.) 
Then in more open order, say 10 feet apart : 
Front rank 10 feet away : : : . 
2nd =,,_=-20 45 : ? , -} (Pos. VIII.) 
ord +. ;, 30 x : : : : 
8th ,, 80 a ; : : : 
Then away. (Pos. IX.) 
Then on the south side: In close order, front rank 5 feet away, next. 
6} say, de. (Pos. X.) 
Then away=Pos. XI. 
_ A few experiments were made inside the observatory with loads of one 
or three men standing on the board floor within 3 or 7 feet of the 
instruments. 
The results obtained were as follows :— 
Result of Loads outside the Observatory. 
% 5 é es Taking the difference between |: 
Roos Level | 22Y reading and the readings 
Time Posi- 2a g a Order | Side | Horizontal |(Mean before anil etter xiest 
tion + N.orS.| Pendulum | of 2 
Sale ends) 7 
£3138 Effect Ty 
Balse 
FT, | FY. " HP. | Level Uy 
12.20 0. —|— _— — _ 15°20 | a 
12.25 0. —|— — _ 49°5 15°60 
12.27 to 12.28 1 90 | 102 close N. 49°5 16°00 Mg 
12.29 to 12.31] II. | 10 | 22 aa N. 50°5 15°70 | +1:25=+042) +025 | +0°34 
12.32 to 12.34 | III. | 90 | 102 - N. 49°0 15°90 | | 
12,35 to 12.37| IV. | 5 | 22 a N. 50°0 15°10 | +1:50=+0:50| +073 | +0°62 
12.38 to 12.40} V. | 90 | 102 N. 480 15°75 
12.41 to 12.43 | VIL 5 | 40 open N. 48:0 15°35 0:00=0'00 | +032 | +0716 
afterwards | | 
12.44 to 12.46 | VIT.} 90 | 102 Eo N. 47-0 15°60 
12.47 to 12.48 | VIII.| 10 | 80! veryopen| N. 47-0 15°15 | +050=017 | 0:00 | +0°08 
12.49 to 12.50 | IX. | 90 | 102 s | N.&S. 46°0 14°50 } 
afterwards 
| 45°25 
12.54 to 12.55] X. 5 | 15 close s. 44°25 15°65 | —1:13=—0°38 —0°65 | —0°52 
12.56 to 12.57 | XI. | 90 | 102 + rs 45°5 15°50 | 
= a 
\ » For lead approaching on N. side readings of H.P. increase.—Level decrease, 
» 3 mts 5 as decrease,—Level increase, 
J One division of the horizontal pendulum=0”, 33, 
