LXXXIV 



THE ROYAL SOCIETY OF CANADA 



The mean diurnal range of Declination varied from a maximum 

 of 12' -5 in August 1913, to a minimum of 4' -2 in February 1914, 

 whilst that of Horizontal Force varied from a maximum of 38 gammas 

 to a minimum of 10 gammas in corresponding months. 



During the year index corrections for the Magnets attached to 

 88 surveyors' Theodolites were determined and supplied to the Sur- 

 veyor-General. 



Assistance and instruction was given to several surveyors in the 

 use of the Total Force Instrument, and in the determination of their 

 constants both before and after their field work. 



Assistance was also given to Mr. French of the Ottawa Dominion 

 Observatory in obtaining comparisons between his field instruments 

 and the Agincourt standards. 



Mr. W. H. McKinlay, who was assigned to the Stefansson Ex- 

 pedition as Magnetician, was given thorough instruction in the use 

 of the Magnetic Instruments and was furnished with all necessary 

 instruments and books for properly carrying on Magnetic Survey 

 work. 



A reduction of the Magnetic data obtained since 1872 at 

 Toronto and Agincourt is also in progress, by Mr. W. E. Jackson, M.A. 



Physics Branch. 



The exploration of the upper atmosphere by means of balloons 

 and kites has been continued satisfactorily, as fourteen records of 

 pressure and temperature from heights ranging between 5 and 10 

 miles above the earth's surface have been obtained. 



The following table gives a summary of the balloon records. 



