Metaphor: "The combined effect was that truth usually went marching on."
This metaphor describes the fact that the Gilbreth children usually tell the truth. Each child has a chart that lists certain things they have to do, like brushing their teeth or weighing themselves and graphing it. Each day they have to check it off once they complete the task. However, sometimes they may cheat and check it off without actually completing the task. But the father, Mr. Gilbreth, can usually tell when his children are lying, so the “truth usually went marching on.” It marches at a steady pace, with no one lying and speeding up or slowing down the procession.
Simile: "...guests would feel at home if they were treated like one of the family."
Though at first this doesn’t seem like a simile, it is comparing treating a guest as a family member. When people tell their guest to “feel at home,” they want them to use everything at will as though they were at home. But they should also try to treat them in the way so that they feel at home. And here, the simile is saying that guests would feel at home if they are treated like a family member.
Metaphor: "'Why does everyone want to make a mountain out of a molehill over such a minor operation?'"
Here, Mr. Gilbreth is using a metaphor. He wants to have his children have a tonsil-removing operation done on them. He thinks it is just a small thing, wanting it done to record it and therefore come up with a more efficient way to do the operation. But everyone else doesn’t think it’s such a small, minor, unimportant thing. They are making a “mountain” out of what, in Mr. Gilbreth’s opinion, is only a small “molehill.”
