APPENDIX C LXXV 



Physics Branch 



This section was occupied chiefly with the establishment of pilot 

 balloon stations at the aerodromes of the Air Board. The equipment 

 and balloons were furnished by the Meteorological Service and the 

 staff at the aerodromes did the work. The single theodolite method 

 for following the balloons was adopted. This method assumes that a 

 balloon will rise at a constant rate depending on the weight of the 

 balloon and the free lift, "The weight that the balloon will just lift." 

 The results of many series of observations have shown that after 

 the first 5 or 6 minutes the rate is very constant as the gradual loss 

 of hydrogen just balances the increased velocity due to diminished air 

 pressure. The rate of ascent adopted for the balloons was 160 metres 

 per minute (525 ft. per minute) and this requires a free lift of from 

 80 to 100 grammes. 



Stations were opened at Vancouver, B.C.; Morley, Alta.; Camp 

 Borden, Toronto and Ottawa, Ont., and Roberval, Que. Toronto 

 and Camp Borden were opened in June ; \'ancouver and Morley about 

 the end of August, and Ottawa and Roberval in October. All the 

 stations were closed during the winter and the one at Morley has 

 been moved to High River, Alta. 



Balloons were despatched from these stations daily unless the 

 day was foggy or the cloud very low. The ascents were made in the 

 morning and at Toronto the results were obtained in time to be used 

 in the forecasts. The highest flight obtained at Toronto was on 

 September 4th ; the balloon was followed for 94 minutes and had 

 reached a height of nearly 50,000 feet when it burst. 



Instruments and equipment for pilot balloon and magnetic 

 observations have been made in the ofiice for a station at Fort Good 

 Hope to be operated for a year or more in connection with the Inter- 

 national work of the Amunsden expedition. 



It was impossible to get the large balloons for carrying instru- 

 ments until January of this year and some flights were made from 

 Kingston, but only about 25 per cent, of the balloons were recovered 

 and the attempt had to be abandoned ; future ascents will take place 

 from Woodstock as before. The Department desires to take this 

 opportunity of thanking Professor Clark, Ph.D., of Queen's Uni- 

 versity, for superintending the ascents at Kingston. 



The apparatus for atmospheric electricity has been redesigned 

 and partly reconstructed but there was not time with the other work 

 that had to be done, to test it out. 



