ich the air had been supposed to contain, but to the want of a
discharge of the phlogistic matter, with which the system was loaded;
the air, when once saturated with it, being no sufficient _menstruum_ to
take it up.

The instantaneous death of animals put into air so vitiated, I still
think is owing to some _stimulus_, which, by causing immediate,
universal and violent convulsions, exhausts the whole of the _vis vitae_
at once; because, as I have observed, the manner of their death is the
very same in all the different kinds of noxious air.

To this section on the subject of diminished, and noxious air, or as it
might have been called _phlogisticated air_, I shall subjoin a letter
which I addressed to Sir John Pringle, on the noxious quality of the
effluvia of putrid marshes, and which was read at a meeting of the Royal
Society, December 16, 1773.

This letter which is printed in the Philosophical Transactions, Vol. 74,
p. 90. is immediately followed by another paper, to which I would refer
my reader. It was written by Dr. Price, who has so greatly distinguished
himself, and done such eminent service to his country, and to mankind,
by his calculations relating to the probabilities of human life, and was
suggested by his hearing this letter read at the Royal Society. It
contains a confirmation of my observations on the noxious effects of
stagnant waters by deductions from Mr. Muret's account of the Bills of
Mortality for a parish situated among marshes, in the district of Vaud,
belonging to the Canton of Bern in Switzerland.

To Sir JOHN PRINGLE, Baronet.

DEAR SIR,

Having pursued my experiments on different kinds of air considerably
farther, in several respects, than I had done when I presented the last
account of them to the Royal Society; and being encouraged by the
favourable notice which the Society has been pleased to take of them, I
shall continue my communications on this subject; but, without waiting
for the result of a variety of processes, which I have now going on, or
of other experiments, which I propose to make, I shall, from time to
time, communicate such detached articles, as I shall have given the most
attention to, and with respect to which, I shall have been the most
successful in my inquiries.

Since the publication of my papers, I have read two treatises, written
by Dr. Alexander, of Edinburgh, and am exceedingly pleased with the
spirit of philosophical inquiry, which they discov