ed in the 1785 paper, which had "since been tried by persons of
distinguished ability in such pursuits without success." It may be noted
here that, while Cavendish adhered to the phlogistic doctrine, he did
not hold it with anything like the tenacity that characterized
Priestley; thus, in his 1784 paper on "Experiments on Air," he remarks
that not only the experiments he is describing, but also "most other
phenomena of nature seem explicable as well, or nearly as well," upon
the Lavoisierian view as upon the commonly believed principle of
phlogiston, and he goes on to give an explanation in terms of the
antiphlogistic hypothesis.

Early in his career Cavendish took up the study of heat, and had he
promptly published his results he might have anticipated Joseph Black as
the discoverer of latent heat and of specific heat. But he made no
reference to his work till 1783, when he presented to the Royal Society
some "Observations on Mr Hutchins's experiments for determining the
degree of cold at which quicksilver freezes." This paper, with others
published in 1786 and 1788, is concerned with the phenomena attending
the freezing of various substances, and is noteworthy because in it he
expresses doubt of the supposition that "the heat of bodies is owing to
their containing more or less of a substance called the matter of heat,"
and inclines to Newton's opinion that it "consists in the internal
motion of the particles of bodies." His "Account of the Meteorological
Apparatus used at the Royal Society's House" (_Phil. Trans._, 1776)
contains remarks on the precautions necessary in making and using
thermometers, a subject which is continued in the following year in a
report signed by him and six others.

Cavendish's last great achievement was his famous series of experiments
to determine the density of the earth (_Phil. Trans._, 1798). The
apparatus he employed was devised by the Rev. John Michell, though he
had the most important parts reconstructed to his own designs; it
depended on measuring the attraction exercised on a horizontal bar,
suspended by a vertical wire and bearing a small lead ball at each end,
by two large masses of lead. (See GRAVITATION.) The figure he gives for
the specific gravity of the earth is 5.48, water being 1, but in fact
the mean of the 29 results he records works out at 5.448. Other
publications of his later years dealt with the height of an aurora seen
in 1784 (_Phil. Trans._, 1790), the civil year