I think chewing tobacco acts as a good stimulant upon anyone engaged in laborious brain work. Smoking, although pleasant, is too violent in its action; and the same remark applies to alcoholic liquors. I am inclined to think that it is better for intellectual workers to perform their labours at night, as after a very long experience of night work, I find my brain is in better condition at that time, especially for experimental work, and when so engaged I almost invariably chew tobacco as a stimulant.

THOS. A. EDISON,
April 4, 1882.