LVI IHE ROYAL SOCIETY OF CANADA 



Magnetic Observations 



During the fiscal year ending March 31, 1919, photographic 

 records of the daily changes in the Magnetic elements were obtained 

 without material loss. At Agincourt the Declination, Horizontal Force 

 and Vertical Force are recorded and at Meanook the Declination. 



During excessively cold weather some difficulty has been experi- 

 enced in keeping the driving mechanism in operation at Meanook, 

 and to overcome this, and also to make provision for installing more 

 complete equipment, it has been proposed to construct an underground 

 room to house the clocks and differential instruments. 



Tables showing the Magnetic character of each day of the year 

 are sent to the International Commission on Terrestrial Magnetism. 

 An analysis of the reports received from all Magnetic observatories 

 in the world is made by the Commission, and a report issued giving 

 the five most quiet days each month and the five most disturbed days, 

 and in conformity with the request of the Commission these days are 

 used in analysing the Magnetic data obtained at both Agincourt 

 and Meanook. The final results for the year 1916 are now in the hands 

 of the printer, and those for 1917 are in course of preparation. 



At the request of the Surveyor-General, index corrections for the 

 compass attachments on 68 surveyor's theodolites were determined 

 at Agincourt, and the results sent to him. Assistance was also given 

 to members of his staff' in standardizing their Total Force instruments 

 at Agincourt both before and after their field w^ork and instructions 

 as to the method of observing. 



Assistance was given to Mr. French of the Dominion Observatory 

 in standardizing his magnetometer, both before and after his field 

 work. 



A special report on the changes taking place in the Magnetic 

 elements during the solar eclipse of June 8, 1918, was made to Dr. 

 Bauer, Director of the Department of Terrestrial Magnetism, Carnegie 

 Institution, Washington, which he has included in his paper published 

 in "Terrestrial Magnetism," Vol. XXIII, Nos. 3 and 4, on "Results 

 of Magnetic Observations Made During the Solar Eclipse of June 

 8, 1918." 



The accompanying tables give a summary of the results obtained 

 at Agincourt and Meanook for the fiscal year 1918-19. 



Magnetic disturbances were of frequent occurrence. The most 

 pronounced were on the following dates: 1918 — April 4, 5; May, 16, 

 17; June, 9, 10; August, 15, 16, September, 21; October, 15, 16. 

 1919— February, 27, 28; March, 20, 21, 22. 



