Those who do not know the torment of the unknown cannot have the joy of discovery.

Priestley [said] that each discovery we make shows us many others that should be made.

A contemporary poet has characterized this sense of the personality of art and of the impersonality of science in these words,-'Art is myself; science is ourselves. '

Mediocre men often have the most acquired knowledge

A discovery is generally an unforeseen relation not included in theory.

Mediocre men often have the most acquired knowledge. It is in the darker. It is in the darker regions of science that great men are recognized; they are marked by ideas which light up phenomena hitherto obscure and carry science forward.

We must never make experiments to confirm our ideas, but simply to control them.