plague in London in 1666 were not perceptible fifteen or twenty
years afterwards. The traces of the most destructive famines in
China and Indostan are by all accounts very soon obliterated.10
It may even be doubted whether Turkey and Egypt are upon an
average much less populous for the plagues that periodically lay
them waste. If the number of people which they contain be less
now than formerly, it is, probably, rather to be attributed to
the tyranny and oppression of the government under which they
groan, and the consequent discouragements to agriculture, than to
the loss which they sustain by the plague. The most tremendous
convulsions of nature, such as volcanic eruptions and
earthquakes, if they do not happen so frequently as to drive away
the inhabitants, or to destroy their spirit of industry, have but
a trifling effect on the average population of any state. Naples,
and the country under Vesuvius, are still very populous,
notwithstanding the repeated eruptions of that mountain. And
Lisbon and Lima are now, probably, nearly in the same state with
regard to population as they were before the last earthquakes.



CHAPTER 7

A probable cause of epidemics--Extracts from Mr Suessmilch's
tables--Periodical returns of sickly seasons to be expected in
certain cases--Proportion of births to burials for short periods
in any country an inadequate criterion of the real average
increase of population--Best criterion of a permanent increase
of population--Great frugality of living one of the causes of
the famines of China and Indostan--Evil tendency of one of the