Economist and demographer Thomas Malthus published in London An essay on the Principle of Population, as it Affects the Future Improvement of Society.
In this rebuttal of the utopian views of William Godwin, Malthus reasoned that populations inscrease by geometrical proportion but food supply only increases arithmetically. He argued that if both food and "the passion between the sexes" are necessary to man's existence, but populations have a much greater tendency to increase than does the food supply, then a "strong and constantly operating check"—such as famine, disease, or sexual deprivation—must be imposed to keep the population level consistent with the level of subsistence.
Malthus's suppositions, though reasonable, were largely intuitive. Though the Essay contained no supporting numerical data, it was extremely influential on passage of the Census Act or Population Act of 1800, which led in 1801 to the first Census of England, Scotland and Wales. Using some of the information gathered in the first census, Malthus supplied factual documentation to support his theories in the greatly expanded second edition of his Essay published in 1803.
Hook & Norman, The Haskell F. Norman Library of Science and Medicine (1991) no. 1431.