Nos. 13 and 14 COMPRESSED- AIR FLYING-MACHINES. 57 



vibration has been taken as the reduced pressure : possibly that 

 portion where the pressure rose ought not to have been included. 



A consideration of this diagram makes it clear that a uniform 

 reduced pressure is not obtainable without the interposition of a 

 large intermediate chamber between the reducing valve and a 

 vibrating engine. The jumps are just visible in the three cylinder 

 engine chronograms. 



It may be mentioned that nine of the successful models described 

 in the Royal Society's Proceedings, representing five distinct types 

 of Flying-machines have been given to the Technological Museum 

 with the object of rendering them at all times accessible to the 

 public, free of charge. The strut of the 48-band machine that 

 made experiments F and G, was used for the 48-band screw 

 machine, and No. 14 is still in the workshop. 



It may be said that it is a waste of time to make machines of 

 such small capabilities, and that no practical good can come of 

 them. But we must not try too much at first ; we must remember 

 that all our inventions are but developments of crude ideas ; that 

 a commercially successful result in a practically unexplored field, 

 cannot possibly be got without an enormous amount of unremuner- 

 ative work. It is the piled-up and recorded experience of many 

 busy brains that produces the luxurious travelling conveniences 

 of to-day that in no way astonish us, and there is no reason for 

 supposing that we shall always be content to keep on the agitated 

 surface of the sea and air, when it is possible to travel in a superior 

 or inferior plane, unimpeded by frictional disturbances. In 

 other words, the surface method of marine transportation now in 

 vogue is analagous to a man wading along shore through the 

 breakers in preference to either swimming beyond the disturbed 

 water, or walking on the beach. 



It does not follow that because the machines described in these 

 pages are of small weight and large area, the insignificant perfor- 

 mances of much larger ones of similar proportions are to be scouted. 

 For instance, 400 lbs. weight of tin-tubing, silk, and steel wire 

 would serve to carry one man five hundred yards at seventeen 



