1915-16.] The Ochil Earthquakes of the Years 1900-1914. 257 
earthquakes, only a few of which are noticed in the newspaper press, it 
is probable that the five shocks mentioned above are only the more promi- 
nent of a long series of tremors and earth-sounds which have escaped record 
owing to the lack of interested observers. 
My investigation of the recent earthquakes has been rendered possible 
through the kindness and courtesy of a large number of persons living in 
different parts of the area considered. More especially am I indebted to 
the following observers who have sent me frequent notices of the earth- 
quakes felt by them : — Airthrey, Mr J. Dempster fand Mr E. J. Sim ; Alva, 
Dr W. L. Cunningham, Mr W. Havery, and Rev. J. Williamson ; Blairlogie, 
the late Mr R. D. Taylor ; Bridge of Allan, the late Surgeon-General Bidie ; 
Dunblane, Dr James Barty and Miss C. H. M. Johnstone; Gogar, Mr J- 
M. Morries, D.L., J.P. ; Greenloaning, Rev. T. Blackwood ; Logie, Rev. M. 
Fergusson; Menstrie, Rev. J. Boyd, Mr T. J. H. Drysdale, and Mr W. H. 
Lindsay ; Red Carr (Blairlogie), Mr T. B. Johnstone ; Tillicoultry, Rev. 
J. Conn and Mr Alex. Scott, Jun. ; Tullibody, Rev. A. Thom.* 
The series of earthquakes studied in this paper began in September 
1900, and ended in December 1914. The numbers of earthquakes recorded 
in successive years are 4 in 1900, 1 in 1903, 10 in 1905, 19 in 1906, 13 in 
1907, 17 in 1908, 18 in 1909, 19 in 1910, 8 in 1911, 74 in 1912, 2 in 1913, 
and 1 in 1914. The total number of shocks observed in 200 months is 
thus 186, or, on an average, very nearly one a month. Three earthquakes 
(those of September 21, 1905, October 20, 1908, and May 3, 1912) were of 
unusual strength and disturbed area, and are referred to in the following 
description as principal earthquakes. The intensity of the shocks is 
determined in terms of the well-known Rossi-Forel scale, or rather of 
the modification of it which I have adopted for use in this country.]* 
II. Description of the Earthquakes.]: 
(1) 1900, September 17, 3.30 p.m. 
A slight shock, felt at Menstrie. 
(2) 1900, September 17, 10.5 p.m. 
A slight shock, felt at Alva. 
* The expenses of the investigations were defrayed from a grant received from the 
Government Research Fund. 
f Geographical Journal , vol. xlvi, 1915, pp. 360-361. 
t The descriptions of the earthquakes numbered 1-42 are abridged from a paper in the 
Quart. Journ. Geol. Soc ., vol. lxiii, 1907, pp. 362-374; those of the earthquakes numbered 
43-82 from papers in the Geological Magazine , vol. v, 1908, pp. 296-309, and vol. vii, 1910, 
pp. 315-320. 
VOL. XXXVI. 
17 
