For a time, however, they worked together; and often did their mother get up at four o'clock in the depth of winter, light their fire, and return to bed after calling them up to the work of self-culture.

Even this did not satisfy their devouring ambition.
There was a bed in the workshop, and they obtained permission to sleep there.

Then they followed their own plans.

The young gardener would sit up till one or two in the morning, and wake his brother, who had gone to bed as soon as he had given up work the night before.
Now he got up and studied through the small hours of the morning until the time came when he had to transfer his industry to shoemaking, or go to school on the appointed days after the distant eight o'clock had come.

His brother had got worn out.