nued that type of work for over fifty years. Similarly, she was the first 
to undertake extensive mapping from air photography and the whole 
of her very large mapping programme is now based on air photography 
and photogrammetrical methods. Almost the whole of Canada 1s cove- 
red with air photography and the National Air Photographic Library 
now has a collection of about two and one-half million prints. 
Yours very truly, 
P. E. PALMER, 
Chief Topographical Engineer 
Ottawa, November 28, 1951 
(!) Air Surveys Limited. — 313 MacLeod Building, — Edmonton, Alberta. 
Aero Surveys Limited. — Vancouver A.M.F. — British Columbia. Mr. F. J. Churko. 
A. E. Simpson Limited. — 8 Laval Road. — Ville St. Laurent. — Montreal 9, Que. 
Spartan Air Service Ltd. — 348 Queen Street. — Ottawa, Ontario. 
Canadian Aero Services Ltd. — 348 Queen Street. — Ottawa, Ontario. 
The Photographie Survey Corporation Ltd. — 1450 O' Connor Drive. — Toronto, Ontario. . 
Arctic Airlines Limited. — N. 7 Hangar, Municipal Airport. — Edmonton, Alta.