The wealth and prosperity of the country are only the comeliness of the body, the fullness of the flesh and fat; but the spirit is independent of them; it requires only muscle, bone and nerve for the true exercise of its functions. We cannot lose our liberty, because we cannot cease to think.

Cavendish was a great Man with extraordinary singularities-His voice was squeaking his manner nervous He was afraid of strangers & seemed when embarrassed to articulate with difficulty-He wore the costume of our grandfathers. Was enormously rich but made no use of his wealth... He Cavendish lived latterly the life of a solitary, came to the Club dinner & to the Royal Society: but received nobody at his home. He was acute sagacious & profound & I think the most accomplished British Philosopher of his time.

Gay-Lussac was quick, lively, ingenious and profound, with great activity of mind and great facility of manipulation. I should place him at the head of all the living chemists in France.

Nothing tends so much to the advancement of knowledge as the application of a new instrument. The native intellectual powers of men in different times are not so much the causes of the different success of their labours, as the peculiar nature of the means and artificial resources in their possession.

The progression of physical science is much more connected with your prosperity than is usually imagined. You owe to experimental philosophy some of the most important and peculiar of your advantages. It is not by foreign conquests chiefly that you are become great, but by a conquest of nature in your own country.

James Watt was equally distinguished as a natural philosopher and chemist; his inventions demonstrate his profound knowledge of those sciences, and that peculiar characteristic of genius - the union of them for practical application.

The most important of my discoveries have been suggested to me by failures.