A man has always to be busy with his thoughts if anything is to be accomplished.

In treating of the oak, I have considered that the species of it growing in warm climates is superior to that which is produced in cold countries. But we must not imagine this to be the case with all woods; on the contrary, the fir timber grown in cold countries is superior to that produced in warm ones, where its growth is rapid.

Whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof.

Antonie van Leeuwenhoek Quotes