Fountain in a Vacuum
   The Fountain in a Vacuum (often called a Fountain in Vacuo) is a perfectly delightful and entertaining  nineteenth century demonstration that is never done today. 

   Volume I of Pike's Illustrated Catalogue of Optical, Mathematical and Philosophical Instruments (New York, 1856) describes it, "The fountain consists of a tall receiver, of glass, about five inches wide in the swell, but contracted at the top, and cemented by a neck at the lower end to a brass cap, having within a jet pipe attached to a stop-cock, which screws into the cap; the whole is mounted on a stand when not in use. To use, the fountain is connected with the air pump by means of the stop-cock and tube; after the air is exhausted out of the receiver, the cock is shut to prevent its return; then the whole is unscrewed from the plate of the receiver, and the lower end of the tub is immersed in a vessel of water; on opening the stop-cock, the pressure of the atmosphere on the surface of the water in the vessel having not counterpoise from the interior of the cylinder, forces up the fluid through the jet-pipe with considerable velocity, which forms a pleasing jet-d'eau, or fountain in vacuo. Price $4.50; larger, $5.00"

   The apparatus at the left is in the collection of the Smithsonian Institution.

REF: Thomas B. Greenslade, Jr., "Demonstrations With a Vacuum: Old Demonstrations For New Vacuum Pumps", The Physics Teacher, 27, 332-341 (1989)

   One teacher, having read the description of the experiment in the paper above, tried it out and reported that it worked well. Unfortunately, this left the apparatus filled with water, and none of my references explained how to drain the water out. 

   Vanderbilt University                Colby College                    Miami University                      Middlebury College

   This fountain in a vacuum has much thicker glass than any others I have seen. It is in the Millington/Barnard Collection at the University Museum at the University of Mississippi in Oxford.

   It is unmarked, but may have been bought by Prof. Frederick Barnard in the second half of the 1850s from Lerebours et Secretan of Paris. The L&S 1853 catalogue does not have a picture of the apparatus, but the price is listed at 30 francs, or about $6.00.

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