450 Mr. A. W. Bickerton on a new Relation 



the motion which would take place under the circumstances sup- 

 posed might be evolved by having recourse to considerations 

 similar to those which Professor Challis has suggested — viz. by 

 considering first what would happen if the column of air were a 

 perfectly rigid bar, next by considering the effect of a slight 

 deviation from perfect rigidity, and finally by inferring from 

 that analogy what would take place in the actual case. I hope 

 hereafter to have an opportunity of developing what has been 

 thus briefly sketched. 



Avranches, October 11, 18/3. 



LIX. On a new Relation between Heat and Static Electricity. 

 By A. W. Bickerton, F.C.S., Associate of the Royal School 

 of Mines, Lecturer on Experimental Science, Winchester College, 

 and the Hartley Institution, Southampton*. 



ON reading the able paper on the above subject by Dr. 

 Guthrie in the October Number of the Philosophical 

 Magazine, it occurred to me that the relationship might be 

 most satisfactorily and easily explained by the assumption that 

 currents of air passing over an electrified body carry off their 

 electricity. The necessity for the assumption of a coercive force 

 existing between these two physical forces (as suggested in the 

 ' Proceedings of the Royal Society ') is thus removed. 



The following experiments seem to me to prove in a most de- 

 cisive manner the correctness of my hypothesis. 



Cold air, or cold gas of any kind, even at considerable pres- 

 sure, when discharged against a charged Peltier's electrometer 

 is incapable of taking away its electricity ; but I found that with 

 a stream of hot air the electroscope was rapidly discharged. 



In one of the Professor's experiments a heated platinum wire 

 is placed above an electrified body, the body being instantly 

 discharged. I thought it possible that the induced electricity 

 on the heated wire might charge the air in its vicinity with elec- 

 tricity ; this charged air passing by attraction down to the elec- 

 trified body would neutralize it. To ascertain if such a current 

 of air existed, I placed the platinum spiral in the upper part 

 vu a gas-jar, a thermometer being passed through the cork 

 so that its bulb was a short distance below the spiral. A brass 

 knob connected with an electric machine was passed up into the 

 jar so as to be close to the thermometer, about 2 inches below 

 the spiral. The knob was also in connexion with a small qua- 

 drant electroscope. The machine was worked; and when the 



* Communicated by the Author. 



