Like Heron's float and Drebbel's thermostat, Watt's centrifugal governor is transparent in its feedback. 和海伦的浮子以及德雷贝尔的恒温器一样，瓦特的这个离心调速器，对于它所接收到的反馈来说，也同样是透明的。
On one side of his ministove, Drebbel attached a glass tube the size of a pen filled with alcohol. 德雷贝尔在小炉子的一边连接了一个钢笔大小的玻璃试管，里面装满了酒精。
