| The pressure and vacuum pump on the right-hand side of
the photograph is listed in the 1927 catalogue of the Central Scientific
Company of Chicago with the notation that the "cylinder is of heavy brass,
nickel plated, 40 cm long by 54 mm in diameter. A vacuum of between 5 and
10 mm may be obtained with this pump. Mounted on an iron base ..... 15.00"
This pump was listed at the same price in the 1941 catalogue,
but by 1950 it had been discontinued.
The black pump appears to be an earlier version of the pump by the same company.
These pumps are in the Greenslade collection.
| "Silbermann Universal Pump. Standing about 67 cm
high, this pump for moving gases consists essentially of a single piston
moved by hand in a barrel 4.03 cm in diameter. Two values in the base open
and close alternately as the piston rises and falls. A stopcock is located
in each of the two side arms, and a third stopcock allows the two side
arms to be directly connected or closed off from each other. Marked "Deleuil
à Paris (in caps). This is item 1925 in Deleuil's catalog of 1865."
From Robert T. Lagemann, The Garland Collection of Classical Physics
Apparatus at Vanderbilt University, (Folio Publishers, Nashville, Tenn.,
1983) pg 174