Translation of "19e" in English

Vient du 19e siècle, du designer William Morris qui disait :

comes from 19th century designer William Morris, who said,

Il a étudié les scientifiques qui lui paraissaient important au 19e siècle.

He studied the scientists considered to be the most significant of the 19th century.

Dans le monde anglophone du 19e siècle, on disait souvent que la masturbation menait à la perte de la mémoire et de la concentration.

In the English world of the 19th century, it was often said that masturbation would lead to a loss of memory and attention.