CHAP. IV.] ADOLESCENCE 1844 TO 1847. 85 



Shortly afterwards (May 25th) he went with his 

 father to the cutler's to choose magnets suitable for 

 experimenting. 



And a little earlier in the same year (March 17), 

 he was taken to hear a lecture 1 on another subject, 

 which was also connected with his subsequent labours, 

 and must have impressed him not a little at the time. 

 This was the discovery by Adams and Leverrier 

 simultaneously, through a striking combination of 

 hypothesis and calculation, of the planet Neptune, 

 which then first " swam into" human "ken." 



The magnetic experiments were continued that 

 autumn at Glenlair, as appears from two entries in 

 the Diary : 



Sept. 3. Walk round by smiddy ; gave steel to be made 

 into bars for magnets for James. 



Sept. 7. James and Eobert (Campbell) most of the 

 time at the smiddy, and got the magnet bars. 



My brother perfectly remembers the magnetising 

 of these bars of steel. 



Lastly, in 1847 unless my memory deceives me 

 James had commenced the study of chemistry, and 

 had taken extra lessons in German. 



There was an odd episode in our school life. To 

 keep our education " abreast of the requirements of 



first, then the composition of white light, then the mixture of colours 

 (not of pigments), then polarisation and the dark lines in the spectrum, 

 and about the same time " the art of squinting," stereoscopic drawing, 

 etc., then colour-blindness, the yellow spot on the retina, etc. 



1 The lecturer was Mr. Nichol, Professor of Astronomy at Glasgow, 

 the father of the distinguished Professor of English Literature in the 

 same University. 



