420 Ninth Annual Report of the 



traced by the pen upon the recording sheet, and the nmratber of 

 miles of wind travel for anj given time is found by counting tfhe 

 number of these notches. It is necessary to replace the recording 

 sheet each day. 



A second wind vane and pair of anemometers are mounted on 

 the tower of McGraw hall, one of the University buildings, stand- 

 ing on the crest of the hill and overlooking the Cayuga valley. 

 These instruments are 12 feet above the roof of the tower, and 140 

 feet from the ground, being thus more exposed to the full force 

 of the wind than those just described. The anemometer for meas- 

 uring horizontal wind currents is of the Richard's construction, 

 consisting of a small wind-mill with 6 inclined vanes radiating 

 from a horizontal axis, which axis, extending into a metal case, 

 makes an electric contact with each hundred revolutions by means 

 of suitable gearing. The entire apparatus revolves freely about 

 a vertical axis in the same manner as an ordinary wind-mill, and 

 is made to face the wind by a broad, wedge-shaped tail at the 

 rear. The vertical axis, which is tubular, passes down into the 

 interior of the tower, and within it are carried the wires which 

 transmit the measurements of wind velocity. 



As the instrument was furnished by the makers, the cylinder 

 upooa which the record of wind direction is traced, was fixed to 

 the lower end of the axis of the wind-vane; but since the 

 registers at the central station are located in the Engineer- 

 ing building, 600 feet distant from the anemometers, a dif- 

 ferent arrangement was necessary. The present device con- 

 sists, firstly, of a fixed metallic ring (a) 3 inches in diameter, 

 through the center of which the lower end of the wind-vane axis 

 passes. Thiis ring is divided into four segments or quadrants, 

 each being connected with a wire passing to the corresponding 

 quadrant of a similar ring (b) on the register in the distant build- 

 ing. A metallic contact piece isecured to the wind-vane axis 

 bears against the quadrants of (a), passing from one to the other 

 (as the direction of the wind changes. The ring (b) also has its 

 coTitact piece, which is secured to the axis of the recording cylin- 

 der, said cylinder being rotated uniformly by Clock work at the 



