They had to work 4 days per week in the 17th century.

They had to work 6 days per week in the 18th century.

Flower came to work in England in the late 15th century.

England found it did not work in the last century.

This approach worked in Europe's colonies in the 19th century, he says.

"Some of these custodians have the same last names as people who worked here in the 18th century," he said.

"I worked with the greatest names in dance in the 20th century."

Early industries included several salt works in the 19th century and a sawmill.

How can we work on it in the 21st century?

For an artist working in the 15th century, some study of the nature of light was essential.