CHAP. XII.] OHM'S LAW. 365 



istic loyalty and humility, Maxwell seems often to 

 have taken more pride in their researches than in his 

 own. To enumerate the men who were thus favoured 

 would be to name many who are now amongst the 

 most efficient teachers of science in the United King- 

 dom. But there can be nothing invidious in making 

 particular mention of those who are named by Maxwell 

 himself in his correspondence, although the omission 

 of other names may be accidental. Besides Mr. W. 

 Garnett, who was his demonstrator in the Laboratory 

 from first to last, he refers with especial satisfaction to 

 the work of Mr. George Chrystal, now Professor of 

 Mathematics in Edinburgh, and to that of Mr. W. D. 

 Niven. 



Mr. Chrystal was encouraged by him to undertake 

 a series of experiments for verifying Ohm's Law re- 

 specting the relation between the current and the 

 electro-motive force in a wire, on which some doubt 

 had been thrown by Weber's theories, and, in an oppo- 

 site direction, by a series of experiments reported to 

 the British Association by Dr. Schuster in 1874. 



In consequence of these doubts a committee was 

 appointed by the British Association consisting of Pro- 

 fessor Maxwell, Professor Everitt, and Dr. Schuster, 

 and the report of this committee was presented to the 

 Association at their annual meeting in Glasgow in 

 1876. The report consists mainly of an account of 

 two experimental investigations planned by Professor 

 Maxwell and carried out in the Cavendish Laboratory 

 by Mr. Chrystal. To this report Mr. Chrystal added 

 a brief account of his experiments on the unilateral 



