Ais'D SEMI-ANNUAL SEISMIC PERIODS. 1137 
Period. 
Maximum. 
Amplitude. 
Annual. 
Semi-annual .... 
December, 5 and March, h 
/ January, h 1 
1 July, b J 
•41 1 
1 
•29 ! 
India. 
55. Oldham, ‘‘ A Catalogue of Indian Earthquakes from the Earliest Time to 
the End of a.d. 1859 ” ; ‘India Geol. Survey Mem.,’ vol. 19, part 3, pp. 1-48. 
Duration of record, 1803-1869. Number of earthquakes, 320 (fig. 15.) 
Fig. 15. 
Period. 
Ma.xinium. 
Amplitude. 
Annual. 
October, b 
•2.5 
Semi-annual .... 
/ Januaiy, a 1 
•38 
3 
“5 
North America. 
56. '''C. W. C. Fuchs, ‘ Statistik der Erdbeben,’ pp. 377-401. 
Duration of record, 1865-1884. Number of earthquakes, 552 (fig. 16). 
This district includes the whole of the continent north of Mexico. 
Period. 
Maximum. 
Amplitude. 
Annual. 
November, b 
•35 
Semi-annual .... 
r April, a I 
I October, a j 
•14 
Annual barometric . 
November, b and December, b 
7 F 
MDCCCXCIir.—A. 
