第八章 The Industrial Revolution 工业革命
书迷正在阅读：神级扮演：从小丑开始、地下城之主、全球天选：开局觉醒百倍经验天赋、妖魔入侵：我成救世大剑仙、名侦探柯南续集、火影：等会，我先戴个写轮眼、神奇宝贝之无尽轮回、这个世界的穿越者有点多、异界游戏王之虚空变、潜伏火箭队，只为超梦
of gravity–actuated reciprocating force pumps housed in the mineshaft. The engine’s downward power stroke raised the pump， priming it and preparing the pumping stroke. At first the phases were controlled by hand， but within ten years an escapement mechanism had been devised worked by a vertical plug tree suspended from the rocking beam which rendered the engine self–acting. ??A number of Newcomen engines were successfully put to use in Britain for draining hitherto unworkable deep mines， with the engine on the surface; these were large machines， requiring a lot of capital to build， and produced about 5 hp (3.7 kW). They were extremely inefficient by modern standards， but when loca