132 THE ROYAL SOCIETY OF CANADA 
This value was determined from all observations made in 1907 and 
for r—30, log (=) —9.995816 
= 
and 14=40, “9.997651 
The rate and error of the chronometer was obtained by comparisons 
with time signals sent over the C. P. R. telegraph system, and by com- 
parison with Toronto Observatory standard at beginning and end of 
the seasons work. 
As errors of the dip needle vary with change of magnetic latitude 
no corrections have been applied to the results of Inclination observa- 
tions. 
The instrumental outfit used during the cruise of the C. G. 8. 
“Arctic” 1908-9 consisted of a Dover Dip circle No. 169; D. T. M. C. I. 
Magnetometer No. 8, ship chronometer Kittel No. 244; 4 second pocket 
chronometer No. 54, Sextant and artificial horizon. These instruments 
were made available for the expedition through the courtesy of the 
Director of the Department of Terrestrial Magnetism of the Carnegie 
Institute of Washington, D.C. 
The Dover Dip circle No. 169 was so modified as to make it practi- 
cally a universal field instrument for high magnetic latitudes. Two 
pairs of dip needles with bar magnets for reversal and two pairs of in- 
tensity magnets were supplied, but only pair No. 5 and 6 for dip and 
pair No. 11 and 12 for intensity were used. 
Constants for this instrument were determined at Agincourt on 
October 28, November 3 and 12, 1909 and resulted as follows :— 
Loaded dip only 
Needle 11 log C, at 15°-4 C=9-70768. 
Deflections only 
Needle pair. Temp. S D Temp. LD, 
11 & 12 15-0 9-50215 15-6 9-35236 
