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.

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.

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.

Every discovery opens a new field for investigation of facts, shows us the imperfection of our theories. It has justly been said, that the greater the circle of light, the greater the boundary of darkness by which it is surrounded.

Mr. Dalton's permanent reputation will rest upon his having discovered a simple principle, universally applicable to the facts of chemistry - in fixing the proportions in which bodies combine, and thus laying the foundation for future labors... his merits in this respect resemble those of Kepler in astronomy.

Profound minds are the most likely to think lightly of the resources of human reason, and it is the superficial thinker who is generally strongest in every kind of unbelief.

Consistency in opinion is the slow poison of intellectual life, the destroyer of its vividness and energy.