I happen to have discovered a direct relation between magnetism and light, also electricity and light, and the field it opens is so large and I think rich.

I have rather, however, been desirous of discovering new facts and new relations dependent on magneto-electric induction, than of exalting the force of those already obtained; being assured that the latter would find their full development hereafter.

I think chemistry is being frittered away by the hairsplitting of the organic chemists; we have new compounds discovered, which scarcely differ from the known ones and when discovered are valueless—very illustrations perhaps of their refinements in analysis, but very little aiding the progress of true science.

The laws of nature, as we understand them, are the foundation of our knowledge in natural things. So much as we know of them has been developed by the successive energies of the highest intellects, exerted through many ages. After a most rigid and scrutinizing examination upon principle and trial, a definite expression has been given to them; they have become, as it were, our belief or trust. From day to day we still examine and test our expressions of them. We have no interest in their retention if erroneous. On the contrary, the greatest discovery a man could make would be to prove that one of these accepted laws was erroneous, and his greatest honour would be the discovery.

Why, sir, there is every probability that you will soon be able to tax it!
Said to William Gladstone, the Chancellor of the Exchequer, when he asked about the practical worth of electricity.

You can hardly imagine how I am struggling to exert my poetical ideas just now for the discovery of analogies & remote figures respecting the earth, Sun & all sorts of things—for I think it is the true way (corrected by judgement) to work out a discovery.