862 The Outline of Science 



cubic feet of hydrogen. At the forward end of the keel is slung 

 a gondola which forms the control cabin and carries the forward 

 engine. Amidships are slung two small wing gondolas each 

 carrying an engine, and near the rear is a larger car containing 

 two engines and an auxiliary control system. The rudders and 

 elevators are aft of this rear car at the tail end of the hull. 



The Safety of Flying 



It is quite a mistaken notion that flying is unsafe and un 

 reliable. During the twelve months October 1920 to September 

 1921, 41,956 passengers were carried in civil aircraft in Great 

 Britain; the mileage covered was approximately 553,700 miles, 

 whilst the number of hours spent in the air by the machines was 

 6,776. For this period of flying the number of passengers killed 

 was four and the number of passengers injured was two. Dur- 

 ing the six months April to September 1921 (half the period 

 under review) one passenger was killed and one injured, out of 

 31,853 carried, and neither of these accidents happened on the 

 regular airways, but simply during joy-riding exhibitions. The 

 casualty rate therefore worked out at .03 passengers killed and 

 .03 passengers injured per thousand carried, whilst 32,200 miles 

 were covered for each accident and 415 hours flown for each 

 accident. These figures do not make civil flying seem unduly 

 dangerous, particularly if a comparison is made with accidents 

 of other methods of transport. Street accidents for 1920 in 

 Britain totalled 57,747, of which 2,837 were fatal. Rail accidents 

 in 1919 totalled 24,915, of which 932 were fatal. These figures 

 will probably surprise many railway users. 



With regard to reliability, the figures are quite convincing, 

 especially when it is remembered that flying is at present in its 

 infancy, and may naturally be expected to grow increasingly 

 efficient as time goes on. Up to the end of September 1921 the 

 figures for the British air transport services between London 

 and Paris which were completed without delay were as follows: 



