138 REPORT OF THE No. 3 



(3) The Mines Department Survey included a small area of vertical 

 photography around Manitouwadge Lake, lying between the Pic and the head- 

 waters of the Black Rivers. Partly to locate this area and also to provide 

 additional map detail, two narrow series of obliques were also run, one from 

 Manitouwadge Lake over the portage route to the Pic, the second from 

 Manitouwadge Lake to the C.P.R. covering the Black River. 



With the exception of the above short series of obliques required by the 

 Mines Department, all aerial survey during the past season was based on vertical 

 photos of sufficient overlap to allow complete stereoscopic examination of the 

 area covered. The total area covered during the season amounted to 3,300 square 

 miles, the total number of exposures 6,200, the total flying hours 168. 



(c) Ground Control. Although in general a net of base control survey data 

 pretty thoroughly covers all of the Province south of the Albany River line, 

 very little is suitable as control for aerial survey strips without additional field 

 work. This is particularly true where vertical control is required. It therefore 

 becomes necessary to obtain additional ground survey data in all areas covered 

 by aerial photography, if maps of acceptable accuracy are to be produced. 



During the past season the Department placed a control party in the field 

 in Block A, described above, with instructions to obtain information for (a) posi- 

 tion of township lines, traversed topographic features, etc., in the photos, (b) spot 

 elevations covering all main topographic features as indicated by stereoscopic 

 examination of photo pairs, (c) forest sample plots in all main forest types. 



This party was under the direction of a graduate Forester and covered a 

 strip following the Superior shore line between Michipicoten Harbour and 

 Batchawan Bay extending inland to an average depth of six miles. In this belt, 

 which approximates 600 square miles, 1,100 elevations were taken and 32 sample 

 plots measured. 



A change in procedure during the present season which transferred the 

 primary plotting of photographic strips to the operating base gave very 

 satisfactory results. The chief benefits are: 



(1) A better use of the time of operating personnel. 



(2) An increased appreciation of sources of error and improvement in 

 operating procedure. 



The drawbacks are negligible except for the necessity of working over a 

 large area from a single base. Where a number of small scattered operations 

 constitute a season's programme the expense and delay of moving and setting 

 up a field draughting room would not ordinarily justify plotting in the field. 



2. Radio Communication: 



The features perhaps most worthy of notice as indicating the development 

 of this work during the past season are: 



(a) The transfer of appointment of radio operators from Head Office to 

 district offices. 



(b) Development of light-weight apparatus (b 1) for inaccessible tower 

 stations, (b 2) for portable work. 



(c) Successful test of aircraft transmitters. 



As radio communication was first established in the Department as a Head 

 Office project and as the details of operation were not familiar to district personnel, 

 it was natural that at the outset full responsibility for operation of radio equipment 

 should be carried by the Head Office radio section. 



After four years' experience, however, and as the use of radio equipment 

 expanded, it seemed advisable to transfer the responsibility for supplying 



