Report of the Kew Committee. 501 



zontal Force, and Vertical Force variations have been obtained unin- 

 terruptedly, and, as in former years, the scale values of all the 

 instruments were determined in January. 



The ordinates of the various photographic curves were then found 

 to be as follows : 



Declinometer : 1 inch = 22'-04. 1 cm. = 8'7. 



Bifilar, January 17, 1894, for 1 inch BTL = 0'0280 foot grain unit. 



1 cm. = 0-00051 C.G.S. unit. 

 Balance, January 16, 1894, for 1 inch 5V= 0'0287 foot grain unit. 



1 cm. = 0-00052 C.G.S. unit. 



In the case of the balance magnetometer it was found necessary to 

 re-adjust the instrument, and as at the same time its sensibility was 

 slightly altered, the scale value was again determined with the 

 following result : 



Balance, January 23, 1894, for 1 inch V= 0'0276 foot grain unit. 



1 cm. = 0-00050 C.G.S. unit. 



As regards magnetic disturbances, the most marked occurred on 

 July 20 and August 20, though on the following dates the instru- 

 ments were a good deal disturbed : 



January 34, February 21, 2325, and 28, March 3031, April 

 1718, June 10, September 1415, 1920, and November 13. 



An examination of the photographic curves of April 27 and 

 July 10, made at the request of Mr. C. Davison, showed slight move- 

 ments in the horizontal force magnet, and smaller ones in the declina- 

 tion magnet. These movements were associated by Mr. Davison 

 (' B.A. Report ' for 1894, p. 151, and ' Nature,' vol. 50, pp. 450451) 

 with the Greek and Constantinople earthquakes of the same dates. 

 Similar examinations have since been made on one or two occasions 

 at the instance of Mr. Davison, and of Professor Tacchini, Omcio 

 Centrale di Meteorologia, Rome, but with negative results. 



The hourly means and diurnal range of the magnetic elements for 

 1894, for the quiet days selected by the Astronomer Royal, will be 

 found in Appendix I. 



The following are the mean results for the entire year : 



Mean Westerly Declination 17 23' 



Mean Horizontal Force G'18251 C.G.S. unit. 



Mean Inclination 67 26''0 



Mean Vertical Force 0'43914 C.G.S. unit. 



A somewhat improved method has been adopted for standardising 

 the curves from the vertical force magnetograph. This introduces 

 no change in the tables of " Diurnal Ranges " in the case either of 



