214 THE ROYAL SOCIETY OF CANADA 



one milliampere with a resistance of one ohm in circuit; thus it was 

 an easy matter to change from linear measurement to electrical 

 constants. 



The cable was laid on December 15, 1920. At different times of 

 the day from December 23, 1920, to February 8, 1921, readings were 

 taken for periods averaging half an hour, from which the following 

 was ascertained: 



(a) The approach, or passing, starting or stopping of a trolley 

 car, even though close by, seemed to have no appreciable effect on the 

 deviations. 



(b) The deflections were both positive and negative and of almost 

 equal occurrence in both directions. 



(c) The larger deviations, those of the order of 1 milliampere, 

 averaged about 1 a minute, though they varied continuously, and 

 sometimes 15 or 20 occurred in a minute. 



(d) Weather conditions seemed to have no effect on the de- 

 flections, which could be correlated with either temperature, pressure, 

 wind or humidity. 



The recording instrument in its final form was set up towards the 

 end of March, 1921, and a continuous record was taken till May, 

 1922. 



Influence of the Radial Line 



The proximity of the Radial Line was a most important factor, 

 as shown by Fig. 1, which is a comparison between the power line 

 kilowatt load curve and the earth current record. Both scales are 

 nearly identical ; the two upper traces show the ordinary night forms 

 of the curves: the kilowatt load curve, A indicated by the arrow, 

 being nearly a straight line at the top of the trace, and the earth 

 current record, curve B, showing a pronounced wave train of three 

 waves from 12.30 a.m. to 2.00 a.m. The two lower curves are the 

 ordinary day forms of the power line, D, and the earth current record 

 C. From this it will be seen that it was an almost impossible task to 

 eliminate from the electric and magnetic disturbances it was desired 

 to study, those caused by the power line. Yet it was impracticable 

 to place the cable in a convenient location free from power line 

 effects. 



Eye Observations of a Thunder Storm 



Many attempts were made to get eye readings, using an auxiliary 

 light, during the intervals when the power was off; but as these were 

 rare and brief, the observations were few. As an instance, on April 



