560 POPULAR LECTURES AND ADDRESSES. 



Dalton, who thought so well of their descriptions 

 that in one instance he was able to say to them, 

 " Those sounds you heard were not human 

 artillery but they were the thunder of an outburst 

 of lightning at sea forty miles south of Holyhead." 

 The two brothers continued pupils of Dalton until 

 the failure of his health ; but for a year after that, 

 and no doubt to the very end, they continued to 

 receive ideas from that great man. It must not be 

 thought that Dalton only taught them arithmetic 

 and trigonometry. I rather emphasize that point 

 with an eye perhaps to the young men who aspire 

 to follow in Joule's footsteps, and upon whom I 

 wish to impress the conviction that it was hard 

 work early begun and persevered in and con- 

 scientiously carried out ; that is the foundation of 

 all great works, whether in literature, philosophy, 

 or science, or in doing good to the world in any 

 possible way. In electricity and electro-magnetism 

 Joule, I think I may say, was wholly self-taught. 

 All he knew he learned from his own reading 

 from reading in text books and in Sturgeon's 

 Annals of Electricity -, and also from conferences 



