Like magic out of a Harry Potter novel, such a metal could contract on command, or swing back and forth like a pendulum.
像这种仿佛出自《哈利·波特》小说中的魔法一般的金属可以按照指令收缩，或者像钟摆那样前后摇摆。
2
On this same tack, you could take the barometer to the top of the building, attach a long rope to it, lower it to just above the street, and then swing it as a pendulum.
根据同样方法，将气压计带到屋顶，拴上一个长绳，直垂地面，像钟摆一样摆动。
3
Will no longer feel that life is too monotonous and old-fashioned as if the old house back and forth of that only know how to swing the pendulum clock units.