Question

The constant air pressure needed to play the hydraulis was supplied by a ?

Answer 1

Answer:

Its pipes stood on top of a wind chest that was connected to a conical wind reservoir. The reservoir was supplied with air by one or two pumps. For the pipes to sound evenly, the wind chest needed steady air pressure. The open bottom of the cone was set in a tall outer container half filled with water.

Explanation:

Answer 2

Answer:

Hydraulic Pump

Explanation

Just did it on Apex