The diary of Thomas Edison, covering the short period from 12 - 21 July 1885. Not much of scientific interest here, just some amusing bits:

It has just occurred to me that the brain may digest certain portions of food, say the ethereal part, as well as the stomach.  Perhaps dandruff is the excreta of the mind — the quantity of this material being directly proportional to the amount of reading one indulges in.  A book on German metaphysics would thus easily ruin a dress suit.

Dot just read to me outlines of her proposed novel, the basis seems to be a marriage under duress.  I told her that in case of a marriage to put in bucketfuls of misery. This would make it realistic.

Saw a woman get into car that [who] was so tall and frightfully thin as well as dried up that my mechanical mind at once conceived the idea that it would be the proper thing to run a lancet into her arm and knee joints and insert automatic self feeding oil cups to diminish the creaking when she walked.