572 Rev. Dr. T. R. Robinson. [June 17, 



Fig. 7. 



On substituting either the bell-jar, with disk terminals, or the tube 

 199 for the voltameter, the deflection of the return static charge was 

 in the same direction as the return current from the voltameter, so that,, 

 as we before stated, no inference can be drawn from the direction of 

 the current as to its being produced by polarisation or a static charge. 

 We think, however, that we have shown conclusively that the effect 

 m the case of a vacuum-tube is due to a static charge, and not to a 

 polarisation of the terminals. We rest our opinion mainly on the fact 

 that a greater deflection is produced, when the potential has not been 

 lessened by a discharge through the tube, than that which occurs after 

 the discharge has taken place, which, it had been surmised, might 

 possibly produce a chemical polarisation. 



XII. " On the Constants of the Cup Anemometer." By the Rev. 

 T. R. Robinson, D.D., F.R.S., &c. Received June 13, 1880. 



(Abstract.) 



In a previous paper the author detailed "experiments made by 

 attaching anemometers to a whirling machine, and the conclusions to 

 which they led. He was however doubtful of the accuracy of the 

 method, and proposed one depending on the action of natural wind. 



