The liquid is then evaporated under a vacuum of 27 to 28 in.
There is no such thing really as a vacuum, any more than there are atoms or ultimate indivisible particles.
Her English vocabulary was growing a word at a time—mostly terms like dust, vacuum, linens, dishes and other domestic terminologies.
The exhaust steam passing from the engine through the blastpipe and the chimney produces a diminution of pressure, or partial vacuum, in the smoke-box roughly proportional to the weight of steam discharged per unit of time.
Evaporation and subsequent distillation under a high vacuum gives crude glycerin.