CONQUEST OF TIME AND SPACE 



grip the water; so of course their propulsive power, 

 combined with the adjustment of the guiding planes, 

 gives the balloon a degree of stability in the air and of 

 buoyancy that it would not otherwise have. Indeed 

 in the case of the first successful dirigible of Santos 

 Dumont, the buoyancy was almost entirely due to 

 the propellers and horizontal rudders, the balloon with 

 its passenger being only slightly less heavy than the 

 air it displaced. 



But it is obvious that a flying machine that must 

 be lighter than air is necessarily of such bulk as to be 

 unwieldy; and all along the ideal that inventors had 

 set themselves was the perfection of a machine that 

 would not be dependent on bulk for its buoyancy; one 

 that could imitate the birds and bats in performing 

 veritable flight in the air rather than merely floating, 

 however accurately directed. In other words, the 

 mechanism sought was a heavier-than-air machine 

 that would fly. 



In that first year of our new century, however, in 

 which Santos Dumont achieved success with his 

 marvelous dirigible, there were not many men of ac- 

 credited scientific standing in the world who thought 

 that this ideal would ever be attained. Indeed, there 

 was only one famous scientist who was making con- 

 spicious efforts toward the practical realization of the 

 ideal. This was Professor Samuel H. Langley of 

 the Smithsonian Institution. Sir Hiram Maxim 

 had indeed, performed some remarkable experiments 

 a few years earlier, constructing a gigantic air 

 machine, which, driven by propellers, lifted itself 

 in the air and made a short flight stabilized by guid- 



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