6o SCIENCE IN AFRICA 



surveys so far made is due partly to the necessity of employing 

 expert personnel for short periods. This difficulty might be met 

 for the British dependencies by the creation of a permanent Air 

 Survey Squad which could be sent to any area where information 

 was desired at the moment. Owing to the long consecutive periods 

 during which African weather conditions are suitable for photo- 

 graphy, one operating aircraft plus strong ground parties could 

 keep a considerable staff of draughtsmen occupied in making 

 topographical maps. In order to make the results available to the 

 various departments interested, liaison officers, to help in inter- 

 preting the photographs, might be required in the initial stages. 

 The desiderata of an Empire air survey organization are there- 

 fore: (i) Two or three aeroplanes with skilled staff. (2) Ground 

 control officers to relate the photographs to fixed triangulation 

 points. (3) A central headquarters with a technical staff to inter- 

 pret the photographs and to prepare maps from them. (4) In the 

 initial stages, experts to demonstrate the value of the photographs 

 to local department officers. 



