316 JAMES CLERK MAXWELL. [CHAP. XL 



The experimental measurements by which the 

 present standard of electrical resistance (the Ohm) 

 was first determined, were made at King's College by 

 a sub-committee of the B.A., consisting of Maxwell, 

 Balfour Stewart, and Fleeming Jenkin, in 1862-63, in 

 accordance with a method proposed by Sir Wm. 

 Thomson. A further experimental measurement was 

 made next year by Maxwell, Fleeming Jenkin, and 

 Charles Hockin (Fellow of St. John's). The import- 

 ance of the work may be estimated by the fact that 

 the system of units then determined by the B.A. 

 Committee was, in the main, adopted by the Electrical 

 Congress which met last year (1881) in Paris, and an 

 International Commission has been appointed by the 

 European Governments to make a redetermination of 

 the standard of resistance first measured by the B.A. 

 Committee. Maxwell's papers on this subject, with 

 those of his fellow- workers, were republished in 1873 

 in a volume edited by Fleeming Jenkin. 1 Many are 

 the references to successful or fruitless " spins " in the 

 home letters of this period. The following quotation 

 will suffice : 



28th January 1864. 



We are going to have a spin with Balfour Stewart to- 

 morrow. I hope we shall have no accidents, for it puts off 

 time so when anything works wrong, and we cannot at first 

 find out the reason, or when a string breaks, and the whole 

 spin has to begin again. . . . However, we hope to bring 

 out our standards by September, and Becker 2 makes them 

 up excellently. 



1 Reports of the Committee on Electrical Standards, appointed by the 

 British Association for the advancement of Science. Spon, London and 

 New York, 1873. 2 Of Messrs. Elliott Brothers. 



