The Ctesibian pump is over two thousand years
old. Firefighters used Ctesibians for centuries. It is a type of force pump.
It is operated by two, four or six men -- sometimes more -- standing on either
end of the "walking beam" to which the piston rods are attached.
The cylinders
are made of copper or brass, the pistons often of wood. There are two valves for
each cylinder and the base of the pump sits in the water source.
An air chamber
below the nozzle acts as a hydraulic accumulator to maintain an even flow of water
out the nozzle.
The water source might be suppied by a bucket brigade of people.
The purpose of the pump is to create a stream of water for putting out the fire.
(This is a still
representation and possibly also a low-resolution image of a pump which is fully
animated in the CD-ROM version of this glossary.) 
