326 JAMES CLERK MAXWELL. [CHAP. XI. 



He also attended several meetings of the British 

 Association, and, in 1870, at the Liverpool meeting, 

 was President of Section A (Mathematics and Physics). 

 His Presidential Address was on the relation of 

 Mathematics and Physics to each other a theme 

 suggested by Professor Sylvester, who had been 

 president of the same section in the previous year. 

 The opening passage, in which he alludes to other 

 recent scientific addresses, is characteristic, and may 

 be quoted here : 



I have endeavoured to follow Mr. Spottiswoode, as with 

 far-reaching vision he distinguishes the systems of science 

 into which phenomena, our knowledge of which is still in the 

 nebulous stage, are growing. I have been carried, by the 

 penetrating insight and forcible expression of Dr. Tyndall, 

 into that sanctuary of minuteness and of power, where mole- 

 cules obey the laws of their existence, clash together in fierce 

 collision, or grapple in yet more fierce embrace, building up 

 in secret the forms of visible things. I have been guided by 

 Professor Sylvester towards those serene heights 



" Where never creeps a cloud or moves a wind, 

 Nor ever falls the least white star of snow, 

 Nor ever lowest roll of thunder moans, 

 Nor sound of human sorrow mounts, to mar 

 Their sacred everlasting calm." 



But who will lead me into that still more hidden and 

 dimmer region where Thought weds Fact, where the mental 

 operation of the mathematician and the physical action of 

 the molecules are seen in their true relation ? Does not the 

 way to it pass through the very den of the metaphysician, 

 strewed with the remains of former explorers and abhorred 

 by every man of science ? . . . 



Two important papers read by Maxwell at the 



