There is no more open door by which you can enter into the study of natural philosophy than by considering the physical phenomena of a candle

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.

... and what good is a baby?

Occasionally and frequently the exercise of the judgment ought to end in absolute reservation. It may be very distasteful, and great fatigue, to suspend a conclusion; but as we are not infallible, so we ought to be cautious; we shall eventually find our advantage, for the man who rests in his position is not so far from right as he who, proceeding in a wrong direction, is ever increasing his distance.

I have far more confidence in the one man who works mentally and bodily at a matter than in the six who merely talk about it.

Magnetic lines of force convey a far better and purer idea than the phrase magnetic current or magnetic flood: it avoids the assumption of a current or of two currents and also of fluids or a fluid, yet conveys a full and useful pictorial idea to the mind.