238 THE HISTORY OF SCIENCE 



to take out patents, or in any way to make money 

 from scientific discovery ; and like Henry, the first 

 Secretary of the Smithsonian Institution (to whom 

 the early development of electro-magnetic machines 

 was due), he preferred to be known as a scientist 

 rather than as an inventor. 



Nevertheless, Langley's desire to construct a large, 

 man-carrying aeroplane ultimately became irresist- 

 ible. Just before the outbreak of the Spanish War 

 in 1898 he felt that such a machine might be of 

 service to his country in the event of hostilities that 

 seemed to him imminent. The attention of President 

 McKinley was called to the matter, and a joint com- 

 mission of Army and Navy officers was appointed to 

 make investigation of the results of Professor Lang- 

 ley's experiments in. aerial navigation. A favorable 

 report having been made by that body, the Board of 

 Ordnance and Fortification recommended a grant of 

 fifty thousand dollars to defray the expenses of fur- 

 ther research. Langley was requested to undertake 

 the construction of a machine which might lead to 

 the development of an engine of war, and in Decem- 

 ber, 1898, he formally agreed to go on with the work. 



He hoped at first to obtain from manufacturers 

 a gasoline engine sufficiently light and sufficiently 

 powerful for a man-carrying machine. After several 

 disappointments, the automobile industry being then 

 in its infancy, he succeeded in constructing a five- 

 cylinder gasoline motor of fifty-two horse-power and 

 weighing only about a hundred and twenty pounds. 

 He also constructed new launching apparatus. After 

 tests with superposed sustaining surfaces, he adhered 

 to the "single-tier plan." There is interesting evi- 



