Prepared chalk or oxide of zinc is pressed upon a smooth plate by a hydraulic press, and the design is drawn upon this in a peculiar ink which hardens the surface wherever it is applied
down stroke hydraulic press
[化] 下冲式水压机
hydraulic pressure
水压[机] 液压, 木压[力]
hydraulic pressure test
[机] 液压试验
steam hydraulic press
[化] 蒸汽液压机
