1 68 PORTRAIT BY COLLIER. 



Magnets, begun in 1 864 at Old Trafford (written in 1882-83)." 

 In this research Joule subjected the magnetic permanence 

 of numerous steel, wrought and cast iron magnets, and two 

 loadstones, to observations extending over 18 years, besides 

 making numerous experiments on the effect of temperature 

 on the intensity of the magnets. 



This work of editing fully explains why Joule ceased 

 his small scale experimental work and his contributions to 

 the Society after 1879, when he read his last paper on 

 " A Method of Checking the Oscillations of a Telescope." 



Although he never fully recovered his health, he was 

 still active. He was President in 1878, and again in 1879, 

 for the last time, as he declined to take the office in 1882. 



During this time he paid frequent visits with his son to 

 his brother in Rothsay. In 1882 he was for some time in 

 London sitting to Collier for his portrait, which was sub- 

 sequently presented to the Royal Society by the members 

 of the Council. In 1883 he and his son spent some time in 

 North Devon. 



The death of his oldest friend and colleague in the 

 Society, Mr. E. W. Binney, which occurred in December, 

 1 88 1, was a great shock to him ; and the Society was 

 never quite the same to Joule afterwards. They were 

 elected members of the Society the same day, January 25, 

 1842, had been co-Secretaries for several years, Vice- 

 Presidents from 185 1 and 1852, and each had held the 

 office of President for 10 years. Though essentially 

 different in temperament, these men had a common ground 

 of sympathy in their love of all that was real in knowledge, 

 and their dislike of all pretence, and there was real love 

 between them. Joule, however, had still many — most of 

 his — friends among the members, and maintained his 



