1 8 Proceedings. 



Ordinary Meeting, October 17th, 1893. 



Professor Arthur Schuster, Ph.D., F.R.S., F.R.A.S., 

 President, in the Chair. 



The thanks of the members were voted to the donors of 

 the books upon the table. 



Reference was made to the deaths, since the close of the 

 previous session, of two of the Society's members — Dr. 

 Charles Clay, elected in 1841, and Mr. Archibald 

 SANDEMAN, M.A., formerly Professor of Mathematics in 

 Owens College, elected in 185 1. 



A bust of Dr. Clay, executed in 1834, and presented to 

 the Society by his executors in accordance with his wish, 

 was exhibited. 



Mr. Faraday alluded to a peculiar deposit of dirt 

 during foggy weather on the spinning cops of yarn in a 

 mill. According to his informant, the deposit increased 

 when the gas was lighted, and so convinced were the firm 

 in question of this that they were proposing to fit up the 

 mill with the electric light on this account alone. A dis- 

 cussion ensued in which Mr. N. BRADLEY, Mr. C. Bailey, 

 Mr. John Boyd, Mr. Angell, Professor Dixon, and the 

 PRESIDENT took part. It was variously suggested that the 

 phenomenon might be due to the heat causing atmospheric 

 currents, and thus bringing more of the polluted air into 

 contact with the cops ; to the fog preventing the escape of 

 the products of combustion into the outer air ; to the 

 vaporisation of minute globules of water floating in the 

 atmosphere, solid matter held by them being thus permitted 

 to descend ; to the greater density of the fog, when it 

 became necessary to light the gas ; and finally to the 

 lighting of the gas merely making the collection of dirt on 



