8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



placed in front of the tunnel and the balance measured both lift and 

 drag. 



Sir Hiram tested airfoils, struts, and airplane parts in his wind 

 tunnel, and also the efficiency of steam condenser pipes.'' 



PAUL LaCOUR 



Two wind tunnels were used by Paul LaCour, of Askov, Denmark, 

 for windmill research. Both were made of sheet iron, cylindrical, 2.2 

 meters long ; one was i meter in diameter and the other ^ meter. The 

 wind was produced by electric blower fans and straightened by radial 

 fins inside the tunnels. A speed of 10 meters per second was used, and 

 this was kept constant by controlling the fan speed, which was read 

 from a tachometer. The testing surfaces and windmill models were 

 placed I meter out in front of the tunnel.'" 



ETIENNE MAREY 



Etienne Marey, of Paris, famous for his chrono])hotographic studies 

 of animal locomotion, in 1899 turned his attention to obtaining photo- 

 graphs of air in motion. This was achieved by the use of narrow 

 bands of smoke in a small, vertical wind tunnel. 



The tunnel was 20 by 30 centimeters in cross-section, with front 

 and sides of plate glass and the back covered with black velvet. The 

 air was drawn down through the tunnel by a small suction fan and 

 straightened by passing through fine silk gauze of very even weave. 



Smoke was supplied through a row of fine tubes at the top of the 

 tunnel and descended in straight bands, clearly showing the flow past 

 small models that were inserted. Photographs were taken by means 

 of a magnesium flash, burnt in a ventilated box close to one side of 

 the tunnel. 



Among the scientists that were interested in these experiments was 

 Samuel P. Langley. He provided funds from the Smithsonian Insti- 

 tution for their continuance, and the next year Marey built a new and 

 improved tunnel. This was 20 by 50 centimeters in cross-section, and 

 the smoke tubes, 60 in number, could be made to vibrate laterally 

 ID times a second. 



* The Aeronautical Annual, 1896, pp. 50-61, illus., Boston. " 



Maxim, Hiram, Artificial and natural flight, pp. 50-61, illus., New York and 

 London, 1908, 



"'LaCour, Paul, Forsogsniollen, pp. 14-15, Copenhagen, 1900. 

 Ingenioren, no. 10, Copenhagen, 1897. 



