nSuppor 



upporhng Pole and 

 pipes carried to a height 

 of 15 feet or more above 

 roof of building. 



R, 



Clockwork 

 Drum . 

 faking 

 21-hours 

 record. 



Revolving Head with 

 Vane, ro keep tube, pom ting 

 n towards wind 



3uct/on 

 by wind <~ 

 pas/- 

 of holes 



-> produced 

 blowing 

 these rows 



5 P 



HEAD OF THE 



ANEMOGRAPH 



W. water in cistern The water likewise 

 Fills par I- oF inside oF Float. 



P, with arrows, sho ws direction along 

 which pressure is exerted. 



S. with arrows, shows direction of 

 sue Hon. 



F, is /'he specially designed Float, which 

 rises & falls with changes in velocity of 

 wind, & so records by the pen attached 

 lo I he rod on top of Float. 



HOW WIND-VELOCITY IS MEASURED. 'THE DINES PRESSURE-TUBE ANEMOGRAPH 



The change of pressure produced by the altering velocity of the wind is transmitted through the pipes from the head of the instru- 

 ment; and the pressure thus exerted upon the surface of the water inside the float causes the float to rise and so brings the recording pen 

 into action. The suction helps the instrument to act more effectively. 



