What do you mean, it's not a fuel-efficient lamp?

"Not a fuel-efficient lamp" means that a person is smart, capable, well-founded, well-informed, with many ideas and high wisdom. A derogatory term refers to someone who is scheming, cunning and wily.

Now "not a fuel-efficient lamp" is a common saying, which has two meanings. One is that someone has a bad temper and is easy to get into trouble; The other is that someone has certain skills, not a mediocre person.

Introduction of provincial oil lamp

At first glance, this kind of oil-saving lamp is the same as ordinary oil lamp, except that its disk wall is a hollow interlayer, and there is a small round mouth on the side of the disk wall for injecting water into the interlayer. It is exactly the same as the situation described by Lu You: "Don't use copper lamps for book lamps, porcelain lamps are the most fuel-efficient. There is a porcelain cup in Shu, and the lip of the cup is filled with water, which can save half of the oil. "

Don't use copper plates to hold oil when reading, porcelain plates are the most fuel-efficient. There is an oil dish in Sichuan, like two oil dishes stacked together, with a sealed edge and a small hole on the side. Inject a small amount of water into the interlayer from the hole, and then pour lamp oil into the oil pan, which can save half of the oil.