Chemistry is necessarily an experimental science: its conclusions are drawn from data, and its principles supported by evidence from facts.

Nature is our kindest friend and best critic in experimental science if we only allow her intimations to fall unbiased on our minds.

All are sure in their days except the most wise ... He is the wisest philosopher who holds his theory with some doubt.

In place of practising wholesome self-abnegation, we ever make the wish the father to the thought: we receive as friendly that which agrees with, we resist with dislike that which opposes us; whereas the very reverse is required by every dictate of common sense.

Lectures which really teach will never be popular; lectures which are popular will never really teach.

I cannot conceive curved lines of force without the conditions of a physical existence in that intermediate space.

I ... express a wish that you may, in your generation, be fit to compare to a candle; that you may, like it, shine as lights to those about you; that, in all your actions, you may justify the beauty of the taper by making your deeds honourable and effectual in the discharge of your duty to your fellow-men.