418 FBA GMENTS O F SCI KNCE. 



whicli so much depends, as well as to nourish indirectly 

 the intellect and will, I took with me four works, com- 

 prising two volumes of poetry, Goet lie's " Farbenlehre," 

 and the work on "Logic" recently published by Mr. Alex- 

 ander Bain. In Goethe, so noble otherwise, I chiefly 

 noticed the self-inflicted hurts of genius, as it broke itself 

 in vain against the philosophy of Newton. Mr. Bain I 

 found, for the most part, learned and practical, shining 

 generally with a dry light, but exhibiting at times a flush 

 of emotional strength, which proved that even logicians 

 share the common fire of humanity. He interested me 

 most when he became the mirror of my own condition. 

 Neither intellectually nor socially is it good for man to be 

 alone, and the sorrows of thought are more patiently borne 

 when we find that they have been experienced by another. 

 From certain passages in his book I could infer that Mr. 

 Bain was no stranger to such sorrows. Speaking for ex- 

 ample of the ebb of intellectual force, which we all from 

 time to time experience, Mr. Bain says: " The uncertainty 

 where to look for the next opening of discovery brings the 

 pain of conflict and the debility of indecision." These 

 words have in them the true ring of personal experience. 

 The action of the investigator is periodic. He grapples 

 with a subject of inquiry; wrestles with it, and exhausts, it 

 may be, both himself and it for the time being. He 

 breathes a space, and then renews the struggle in another 

 field. Now this period of halting between two investi- 

 gations is not always one of pure repose. It is often a 

 period of doubt and discomfort of gloom and ennui. 

 " The uncertainty where to look for the next opening 

 of discovery brings the pain of conflict and the debility of 

 indecision." It was under such conditions that I had to 

 equip myself for the hour and the ordeal that are now 

 corne. 



The disciplines of common life are, in great part, exer- 

 cises in the relations of space, or in the mental grouping 

 of bodies in space; and, by such exercises, the public 

 mind is, to some extent, prepared for the reception of 

 physical conceptions. Assuming this preparation on your 

 part, the wish gradually grew within me to trace, and to 

 enable you to trace, some of the more occult features and 

 operations of Light and Color. I wished, if possible, 



