The sentences in this passage that provide evidence are sentence 4, which gives examples of the kinds of careers where people might have to stay up late and thus sleep late. Shift workers are one example if they work the night shift and then sleep during the day. In Ben Franklin's time there was no electricity so it was much rarer to work in the evening hours or overnight. People got up early to take advantage of the daylight. In sentence number 6, they give examples of the disadvantages of working nights like being sleepy at the wheel or suffering from exhaustion.
