Signedon plaque, top board: E. S. RITCHIE / BOSTON, MASS.
FunctionAn air-pump is an instrument used to produce a vacuum in order to study nature under controlled environmental conditions. It became one of the most important scientific instruments of natural philosophy as early as the late seventeenth century. With the electrostatic machine, the air-pump became in time not only a genuine research tool but an important pedagogical apparatus in the lecturer-demonstrator's arsenal. Ritchie, as most instrument makers, sold several kinds of these, ranging in price from $25 to $300. This was is masterpiece, which he sold $300 in 1855.
In this model, a glass bell jar has been put on the plate. The experiments would have taken place inside the bell jar.
This is how Ritchie introduced his air pumps in 1855: "As so many experiments depend on the perfection of this instrument, I have spared no expense in my machinery for making every part in the most perfect manner. I have introduced some improvements in its construction. My pumps are made on the principle of Leslie, but much improved."
Primary SourcesEdward S. Ritchie, Illustrated Catalogue of Philosophical Apparatus (Boston, 1855), 1-3.
ProvenanceFrom the Department of Geology and Geography, Harvard University.