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The steam was invented ...James Watt, who worked ...many years before he could make the instruments ...which he perfected his machine. ..first he worked ...primitive tools so he could not make his engine well-regulated. The old machine was kept going ...a boy who stood by it and let... the air ...means of which the steam was condensed at every revolution. ..this machine, though it was imperfect, some work was done and it had been used ...a large mine-owner (шахтовладелец) to pump out the water. The first efficient steam-engine was made ...a Birmingham firm and it was soon used...nearly every manufacturer. The revolution in industry made ...this machine was extremely great.