l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 62 



The Conservatoire National des Arts and Metiers, corresponding 

 to our Bureau of Standards, does some aeronautical work in cali- 

 brating instruments, testing materials and motors, and furnishes 

 a " mouline Renard " — a standardized revolving bar with paddles at 

 either end — for attachment to a motor to determine its power at 

 various speeds of rotation. 



By the use of automobiles on a smooth road Chauviere has tested 

 screw propellers mounted above the vehicle and advancing at natural 

 working speed, and the Due de Guiche has measured the lift, drift 

 and pressure distribution on aerofoils of considerable size. The 

 accuracy of the automobile method has, however, still to be proved 

 satisfactory. The Chauviere propeller experiments are now made 

 at St. Cyr Institut ; but the researches of the Due de Guiche still 

 continue, and are reviewed from time to time in aeronautical litera- 

 ture. The earlier reports comprise two volumes published by 

 Hachette, Paris. 



GERMAN AERONAUTICAL LABORATORIES 

 The Gottingen aerodynamical laboratory, apart from the con- 

 structional and executive departments, is a one-story brick building, 

 in size about 30 by 40 feet, comprising a wind-tunnel and two rooms, 

 one for desk work, the other for instrumental observations. It stands 

 alone, in a remote little meadow on the outskirts of the city, about 

 fifteen minutes walk from Prof. Prandtl's university headquarters. 

 It is very cheaply constructed, lighted by electricity, and heated by 

 a little stove in one office. 



The zviiid-titiniel consists of a continuous closed channel, two 

 meters square in cross-section, running round the four walls of 

 the main room. Through this tunnel the air is forced in a steady 

 closed circulation by a screw ventilator two meters in diameter, 

 belt driven from a thirty-horse electric motor placed in a little ofif 

 room. As the blast from the blower is too fast along the tunnel 

 walls, it is accelerated at the center of the stream by use of sheet 

 metal fixtures placed in it near the screw, which also help to elimi- 

 nate whirls. The air stream next passes through a honeycomb 

 (fig. i), made of 400 equal sheet metal cells, each about 4 inches 

 square and 20 long, the sheet metal being in two thicknesses, or two 

 ply, so that either cell can be constricted at will by spreading the 

 cell wall inwardly. Actually, many of the cell walls were so con- 

 stricted. In fact, the honeycomb looked badly distorted as if much 

 time had been spent in adjusting the cells so that each should deliver 



