Robert Boyle was a
central figure in the investigations of the natural world by means
of experimentation that were carried out by the members of the Royal
Society and other experimental philosophers in England and elsewhere
in the seventeenth century. Boyle already had a long-standing interest
in pneumatics when he read of the experiments (carried out in 1644)
by Evangelista Torricelli (1608-1647) and Vincenzo Viviani (1622-1703)
that effectively created a barometer. They had filled a tube with
mercury, closed it at the end, and inverted it into a dish of mercury,
whereupon the column sank to about 760 millimeters above the dish,
leaving an empty space in the tube above the mercury. Torricelli
concluded that his instrument might be used to measure atmospheric
pressure. The experiment was of great philosophical interest because
it seemed to disprove the Aristotelian dictum that "nature
abhors a vacuum."
Boyle heard of these
experiments by the early 1650s and repeated
them. He then attempted to create a variation of the apparatus that
would allow the introduction of larger objects into the empty space,
and thus allow further investigation of the nature of air. He was
aided again by hearing of experiments carried out in 1647 by the
mayor of Magdeburg, Otto Guericke. Guericke built an air suction
pump with a cylinder, a piston, and two flap valves. Boyle set for
his assistant Robert Hooke (1635-1703) the problem of creating an
air pump that was suitable for carrying out experiments concerning
the nature of air. The image that appears in Boyle's treatise, New
Experiments Physico-Mechanical Touching the Spring of the Air,
displays the apparatus that Hooke devised and that was used for
the numerous experiments described in the treatise.
Boyle provides a complete
description of the apparatus, which included two main parts: the
glass vessel and a pump to draw the air out. He labels and describes
each part, including an account of the way in which it was constructed
and the materials with which it was made. These details contribute
to the immediacy of the descriptions of the experiments. They suggest
that Boyle is not referring to Aristotelian common experience (agreed
upon by everyone) but rather to particular experiments, carried
out at a particular time by specific experimenters, watched by reliable
witnesses, and using a specific, complex apparatus.
Boyle's phrase, the "spring of the air,"
points to a major focus of the experiments, the capacity of the
air to exert pressure and to expand. Boyle was cautious about overdrawing
his conclusions. For example, he did not claim that the air pump
created a true vacuum, that is, that the space became truly empty.
Rather, he referred to the removal of "ordinary air,"
leaving open whether or not the operational vacuum was a true one.
This refusal was part of his methodology in which he claimed to
be dealing only in "facts" rather than hypothesis and
By the end of the
seventeenth century, the principle that the atmosphere was a fluid
possessing weight and that its pressure could be excluded from the
interior of a closed vessel so as to obtain a vacuum was incorporated
into the construction of the first steam engines, the technology
that came eventually to define the course of the Industrial Revolution.
New York University
Boyle, Robert. The Works of Robert Boyle.
Vol. 1, Experiments Physico-Mechanical touching the Spring
and Weight of Air. Edited by Michael Hunter and Edward Davis.
Brookfield, Vermont: Pickering and Chatto, 1999-2000.
Dear, Peter. Discipline and Experience:
The Mathematical Way in the Scientific Revolution. Chicago:
University of Chicago Press, 1995.
Dear, Peter. Revolutionizing the Sciences:
European Knowledge and Its Ambitions, 1500-1700. Princeton:
Princeton University Press, 2001.
Frank, Robert G. Harvey and the Oxford
Physiologists: Scientific Ideas and Social Interaction. Berkeley:
University of California Press, 1980.
Shapin, Steven, and Simon Schaffer.
Leviathan and the Air-pump: Hobbes, Boyle, and the Experimental
Life. Princeton: Princeton University Press, 1985.