In consequence of suggestions in letters and in reviews, some changes have been made in this edition.

Very little new matter has been added; but some letters have been left out; and other letters, and some of the lectures and journals have been shortened.

Two or three errors, which came from misapprehensions in conversation, have been corrected.

The most important mistake relates to the loaf of bread which Faraday had weekly when nine years old. I wrongly understood that it came from the temporary help which was given to the working class in London during the famine of 1801. I was too easily led into this error by my wish to show the height of the rise of Faraday by contrasting it with the lowliness of his starting point. I ought to have been content with the few words which he wrote. “My education was of the most ordinary description, consisting of little more than the rudiments of reading, writing, and arithmetic, at a common day school. My hours out of school were passed at home” (in the mews) “and in the streets.”

This leaves no doubt that Faraday rose from that large class which lives by the hardest muscular labour, and can give but little for mental food; and yet by his own brain-work he became in his day the foremost of that small class which, by the mind alone, makes the glory of humanity.