Natural Philosophy 177The assimilation of experimental philosophy with natural philosophy
was accomplished by the distinctive science of the eighteenth century,
electricity, and by the creation of new audiences for the demonstration
of natural knowledge. As the practice of witnessing experiments dimin-
ished at the major learned societies in favor of reports printed in their
publications, a new audience grew up consisting of well- off people curi-
ous enough about the latest fi ndings in natural philosophy to spare an
evening for it from cards. Their expectations put an even higher premium
on experiments easily seen and appreciated by groups. Schools provided
another considerable consumer of demonstrations. Instrument makers
and booksellers furnished the necessaries. The fi ne points of anatomical
or microscopic investigations had little to offer philosophical showmen.
They stuck to mechanics, hydrostatics, and pneumatics, and their appli-
cations as exhibited in models of machines—pile drivers, driving bells,
fi re engines, steam engines, and so on. At midcentury, demonstrations
of electricity joined and then soon led the repertoire. Lecture courses of
the time typically bore the title “Natural and experimental philosophy,”
meaning experiments and their interpretations.^8
The electrical fi re producible by electrostatic generators and the shocks
procurable from condensers after the invention of the Leyden jar in 1745
made wonderful games and displays. The electrical kiss, the simulation
of lightning, the electrocution of birds, and shock therapy became the
signatures of natural philosophy. According to Daniel Jenisch’s Geist und
Character des achtzehnten Jahrhunderts, which portrayed the dying century
from the perspective of 1800, “Electricity and its wonderful effects are
without doubt the most remarkable and useful discoveries with which
the eighteenth century has enriched [natural philosophy].”^9 ( Jenisch was
a prolifi c polymath priest and professor, some of whose works won prizes
from the Berlin Academy of Sciences.^10 ) Together with other branches of
physica particularis (pneumatics, heat, light, magnetism, and often also
meteorology) and physica generalis (statics and dynamics of solids and liq-
uids, and perhaps qualitative Newtonian astronomy), electricity defi ned
the subject of natural philosophy around 1750.^11
During the last third of the eighteenth century the narrowly focused
natural and experimental philosophy of midcentury underwent a major
expansion in two directions. For one, it again took in parts of chemistry,
particularly the theory and practice of the gases discovered in the 1760s
and 1770s and, later, the principles of Lavoisier’s system and nomencla-
ture. These provinces of chemistry and the sorts of experiments that sup-
ported them were closer to the concerns and methods of experimental
philosophy than the older chemical recipes and reasonings. Lavoisier him-