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CIX. On the Measurement of the Viscosity of Gases. 

 By Prof. A. Anderson *. 



A SIMPLE method, suitable for laboratory students, of 

 finding the coefficient of viscosity of air or any gas 

 will be understood readily from the figure. A bulb furnished 

 with a vertical tube communicates with a long capillary tube 

 of uniform bore which can be opened or closed by means of 

 the pinch-cock P. To this vertical tube is connected by 



Fig. 1. 



flexible tubing another vertical tube AB which can be 

 moved readily up and down. These tubes contain mercury 

 the levels of the two surfaces of which can be read off on 

 fixed graduated vertical scales. The volume of the bulb to 

 a fixed mark on the stem is supposed to be known. 



Let the pinch-cock be closed and suppose the levels of the 



* Communicated by the Author. 



