COMMEMORATIVE ADDRESS 3 



fessor George F. Barker, one of the editors of that journal. It is inter- 

 esting as marking the beginning of his optical work. For a year, or 

 perhaps for several years previous to this time, however, he had been 

 busily engaged on what proved to be, in its influence upon his future 

 career, the most important work of his life. To climb the ladder of 

 reputation and success by simple, easy steps might have contented 

 Eowland, but it would have been quite out of harmony with his bold 

 spirit, his extraordinary power of analysis and his quick recognition of 

 the relation of things. By the aid of apparatus entirely of his own 

 construction and by methods of his own devising, he had made an inves- 

 tigation both theoretical and experimental of the magnetic permea- 

 bility and the maximum magnetization of iron, steel and nickel, a 

 subject in which he had been interested in his boyhood. On June 9, 

 1873, in a letter to his sister, he says: " I have just sent off the results 

 of my experiments to the publisher and expect considerable from it; 

 not, however, filthy lucre, but good, substantial reputation." What 

 he did get from it, at first, was only disappointment and discourage- 

 ment. It was more than once rejected because it was not understood, 

 and finally he ventured to send it to Clerk Maxwell, in England, by 

 whose keen insight and profound knowledge of the subject it was 

 instantly recognized and appraised at its full value. Eegretting that 

 the temporary suspension of meetings made it impossible for him to 

 present the paper at once to the Eoyal Society, Maxwell said he would 

 do the next best thing, which was to send it to the Philosophical Maga- 

 zine for immediate publication, and in that journal it appeared in 

 August, 1873, Maxwell himself having corrected the proofs to avoid 

 delay. The importance of the paper was promptly recognized by 

 European physicists, and abroad, if not at home, Eowland at once took 

 high rank as an investigator. 



In this research he unquestionably anticipated all others in the dis- 

 covery and announcement of the beautifully simple law of the magnetic 

 circuit, the magnetic analogue of Ohm's law, and thus laid the founda- 

 tion for the accurate measurement and study of magnetic permea- 

 bility, the importance of which, both in theory and practice during 

 recent years, it is difficult to overestimate. It has always seemed to 

 me that when consideration is given to his age, his training, and the 

 conditions under which his work was done, this early paper gives a 

 better measure of Eowland's genius than almost any performance of 

 his riper years. During the next year or two he continued to work 

 along the same lines in Troy, publishing not many, but occasional, 



