64 



L. HAEGRAVE. 



shown under the boiler. The total weight of the motor exclusive 

 of water and kerosene is 36*5 pounds. 



The principle that long continued thought on any subject must 

 tend to a clearer view of the detail connected therewith, has 

 encouraged me to state some considerations as to the disposition 

 of the supporting surfaces of flying machines that do not seem to 

 have yet struck other experimenters. 



It has been usual to make the lifting surface in one or more 

 pieces rigidly connected to the weight to be lifted. In the machine 

 for the engine, Figs. 3 and 4, it is intended to depart considerably 

 from this practice by dividing the required surface into numerous 

 small aeroplanes, all attached to the weight by one wire. 



The aeroplane derives its lifting power either from moving air 

 passing it when attached to the earth or from being moved hori- 

 zontally through calm air; in either case there is no necessity for 

 the aeroplanes to be connected to the weight by rigid booms and 

 numerous stays, as the lift and drift can act only in tension and 

 in one vertical plane. By dividing the surface into a number of 

 small planes, any refinement of curve may be introduced with the 

 certainty that the advantage accruing therefrom will be effectively 

 used, and that the head resistance will be reduced to a minimum. 



It will be obvious that forty aeroplanes of ten square feet area 

 each can be constructed with much less material for spreading 

 them horizontally than one plane of four hundred square feet area. 

 In fact we are substituting arithmetical for geometrical progression 

 in the weight of our surfaces and their head resistance, and lifting 

 our machine pound by pound with foot by foot of added surface. 

 We are also able to unite very large and therefore more efficient 

 engines with the extraordinary lifting power known to exist in 

 small and carefully curved aeroplanes. You will gather from 

 these remarks that the proposed flying machine will be a rather 

 tall structure, and that fact alone will make it extremely easy to 

 work and certain in its action. 



The most suitable time for experimenting will be when the 

 wind velocity is slightly below that at which the machine is 



