182 REPORT—1899. 
11. Cape of Good Hope: Royal Observatory. Director, Davin G11, Esq., F.2.S, 
The instrument was mounted on a concrete pier based on a rock 
foundation, and was experimentally started on June 20, 1899. 
At first difficulties were experienced in attaining the necessary amount 
of sensitiveness. There appeared to be a large amount of friction which 
prevented the boom swinging freely. This, however, was remedied by a 
readjustment of the balance weights, and the instrument has been re- 
cording with occasional interruption since July 1i. 
The principal events so far registered are as below, the times being 
referred to Greenwich mean civil time. 
The Cape Register. 
1899. 
1. July 14— 
H M. 
Preliminary tremors . : : i b 18 47:2 
Commencement of decided motion : LAL Te? 
End of decided motion 5 : ‘ . 1b 32:6 
Maximum amplitude, 3 mm. 
Also recorded at Shide. 
2. July 18— 
H. OM. 
Preliminary tremors . 2 : : «2 poll “1456 
Commencement of decided motion : 2 2180 
Maximum amplitude, 3 mm. 
Times of maxima, 2]h. 23°2m., 2lh. 34:4m. 
3. July 20— 
Slight tremors from about Oh. to 7h., commencement and end not well 
marked. More violent disturbance for about 10m.; maximum dis- 
placement 23 mm. at 3h. 40m. 
4. July 20— 
Disturbance commenced at 19h. 17m. The motion subsided from 
19h. 26:8m. but restarted at 19h. 44:2m., and finally ceased at 19h. 595m. 
5. July 27— 
Disturbance commenced without preliminary tremors at 15h. 4°7m. 
Maximum displacement about 24m. after commencement. Greatest 
amplitude of swing, 9mm. Total duration, 45m., with calm interval of 
10m. 
6. July 31—Violent disturbance. 
H. M. 
Preliminary tremors. - ; . s + 2 42:5 
Commencement of decided motion. . 2 46:0 
End of decided motion 5 ‘= : By sits} 
The early part of this disturbance shows signs of a periodic character with a 
period declining from about 6m. to about 3m. The latter half is much more - 
irregular in form. Well-marked maxima at 2h. 47m., 2h. 52m., 2h. 57m., 3h. 1m., 
3h. 4m., and 3h. 25m. Displacements from centre amounting to 20 mm. 
Several insignificant disturbances have also been recorded, besides those quoted 
above. 
