been established at Grenelles, near Paris; but it was insufficient for
the immense demand. Chaptal soon, by his skill and activity, so improved
this establishment, that it supplied all that was wanted, and this at a
time when France had about 1,400,000 soldiers.[3]

[3] The theory of this artificial formation of saltpetre is
detailed by Chaptal, in _Annales de Chimie_, tom. xx.--The bulk
of saltpetre used in this country is brought from the East
Indies, where, at certain seasons of the year, it is found
deposited on the surface of the soil. It is swept off once or
twice a week, and as often renewed. At Apulia, near Naples,
there is a bed containing 40 per cent. of it; and in Switzerland
the farmers extract it in abundance from the earth under the
stalls of the cattle. In the reign of Charles I. great attention
was paid to the making of saltpetre in England. Certain
patentees were authorized by royal proclamation to dig up the
floors of all dove-houses, stables, &c. In France, the plaster
of old walls is washed to separate the nitrate of lime, which is
a soluble salt, and this, by means of potash, or muriate of
potash, is afterwards converted into nitre. Mr. Bowles, in his
Introduction to the Natural History of Spain, assures us there
is enough saltpetre in that country to supply all Europe for
ever.

Chaptal returned to Montpellier in 1794, and soon obtained a place in
the administration of the department of Herault, and a professorship of
chemistry in the university of Montpellier, which the Directory created
expressly as a reward for his services. In 1798, Chaptal revisited
Paris, and aided the Revolution by which, in 1799, Buonaparte became
First Consul. In the following year Chaptal was made Minister of the