Aboard the HMS Beagle in 1831, Charles Darwin began journaling.

He never stopped.

He’d take a pencil and paper into the field with him and jot down observations and ideas. When he was back on board, he’d then copy those quick drawings into his notebooks with a pen. He typically did so after lunch along with his captain, Robert FitzRoy.

Darwin wrote:

Let the collector’s motto be ‘Trust nothing to memory;’ for the memory becomes a fickle guardian when one interesting object is succeeded by another still more interesting.”

Darwin explains that a naturalist must take “copious notes,” not for publication, but for himself. Referencing Bacon, he says, “Reading maketh a full man, conference a ready man, and writing an exact man.”

Here are what some entries say:

Solitude on board enervating heat comfort hard to look forward pleasures in prospect do not wish for cold night [delicious] sea calm sky not blue.

Always think of home

Nobody knows pleasure of reading till a few days of such indolence

The notebooks also include over 300 sketches and doodles.