The boundary between equipment built for scientific purposes, and
that made for practical purposes, is not clear. Thus our collection
includes such varied items as air pumps, sextants, and slide rules.
One great museological advantage of old instruments is that it is
usually possible to see how they work - unlike today's 'black boxes'.
Even if the principle is obscure, for example in the Wimshurst machine
illustrated below, the mechanical interaction of parts is usually
relatively easy for the layman to follow.