He observed when people were machining cannon barrels, a lot of heat was generated, and there was a lot of work done.
他发现人们在制作炮管时，会产生大量的热，同时有大量的做功。
2
You can take heat energy and convert it to work energy and vice versa, and it doesn't say anything about that you have to waste heat if you're going to transform heat into work.