Magdeburg Hemispheres

A working model to demonstrate the principles involved in the action of a force-pump.

Cylinder is 25 x 350 mm dia x overall height. It is provided with a non-return float valve at its lower end. Lower part of the cylinder has an outlet side tube communicating with the lower end of another cylinder also equipped with non-return valve. Outlet tube from the secondary cylinder is drawn out into a jet to demonstrate ability of force pump to eject water at high pressure.

A glass tube of 6mm bore is enclosed in an enamelled and lacquered brass case, mounted on a polished wooden board with plates for fixing on wall. Open plate reflectors, ring and screws for vertical adjustments. A dual scale graduated in 25 to 32 inches and 640 to 810mm is read by verniers moving by rack and pinion, reading to 0.002 inch and 0.1mm are enclosed in a glass cylinder. A glass cistern at the lower end of barometer is provided with an ivory point to adjust the level of mercury. A thermometer -10 to 50C is provided on the wooden board. Supplied without mercury and glass case.