52 LAWRENCE HARGRAVE. 



Mr. Dixon, Chairman — In proposing a vote of thanks quoted a 

 proverb from the Talmud, ' that many persons are honest because 

 they never had occasion to steal.' Fining may be a deterrent, bub 

 it is better to warn persons what the consequences would be and so 

 prevent people from attempting to act dishonestly, whilst publicity 

 would compel those in the meat trade to take notice of M. Loir's 

 suggestion. 



Nos. 13 and U COMPRESSED-AIR FLYING-MACHINES. 

 By Lawrence Hargrave. 



[With Plates i. - x., inclusive.] 



[Bead before the Royal Society, N.S. Wales, July 1, 1891.'] 



The essential features of No. 13 are a two inch air receiver, four 

 feet seven inches in length; 2952 square inches of floating surface, 

 2927 square inches of which are in the body-plane, and 22-3 % of 

 the total area is in advance of the centre of gravity; a three cylinder 

 engine of the Brotherhood type is placed astride of the forward 

 end of the receiver, driving a two-bladed screw at the bow of the 

 machine. The whole apparatus weighing 46*86 oz, when it is 

 charged with air at a pressure of 230 lbs. per square inch. Plates 

 I., n., in., iv. show this machine in detail. 



The trial of this type of Flying-machine afforded facilities for 

 comparing, in a rough sort of way, the theoretical and actual work 

 done by the engine. A diagram showing time, revolutions, receiver 

 pressure, and reduced pressure can be taken from the stationary 

 machine with the screw on. The screw can then be removed and 

 a pulley substituted so that the engine can lift a weight. The 



