Accurate and minute measurement seems to the non-scientific imagination, a less lofty and dignified work than looking for something new. But nearly all the grandest discoveries of science have been but the rewards of accurate measurement and patient long-continued labour in the minute sifting of numerical results.

Science is bound, by the everlasting vow of honour, to face fearlessly every problem which can be fairly presented to it.

When you can measure what you are speaking about, and express it in numbers, you know something about it.

Simplification of modes of proof is not merely an indication of advance in our knowledge of a subject, but is also the surest guarantee of readiness for farther progress.

Heavier-than-air flying machines are impossible.

The vortex theory [of the atom] is only a dream. Itself unproven, it can prove nothing, and any speculations founded upon it are mere dreams about dreams.

[Referring to Fourier's mathematical theory of the conduction of heat] ... Fourier's great mathematical poem.