The increase of population can be carried furthest in the countries where the people are content to live the most poorly and to consume the least produce of the soil. In countries where all the peasants and labourers are accustomed to eat meat and drink wine, beer, etc. so many inhabitants cannot be supported.
Sir William Petty, and after him Mr Davenant, Inspector of the Customs in England, seem to depart from nature when they try to estimate the propagation of the race by progressive generations from Adam, the first father. Their calculations seem to be purely imaginary and drawn up at hazard. On the basis of what they have seen of the actual birth rate in certain districts, how could they explain the decrease of those innumerable people formerly found in Asia, Egypt, etc. and even in Europe? If seventeen centuries ago there were 26 millions of people in Italy, now reduced to 6 million at most, how can it be determined by the progressions of Mr King that England which today contains 5 or 6 millions of inhabitants will probably have 13 millions in a certain number of years? We see daily that Englishmen, in general, consume more of the produce of the land than their fathers did, and this is the real reason why there are fewer inhabitants than in the past.
Men multiply like mice in a barn if they have unlimited means of subsistence; and the English in the colonies will become more numerous in proportion in three generations than they would be in thirty in England, because in the colonies they find for cultivation new tracts of land from which they drive the savages.
In all countries at all times men have waged wars for the land and the means of subsistence. When wars have destroyed or diminished the population of a country, the savages and civilised nations soon repopulate in in times of peace; especially when the prince and the proprietors of land lend their encouragement.
A state which has conquered several provinces may, by tribute imposed on the vanquished, acquire an increase of subsistence for its own people. The Romans drew a great part of their subsistence from Egypt, Sicily and Africa and that is why Italy then contained so many inhabitants.
A state where mines are found, having manufactures which do not require much of the produce of the land to send them into foreign countries, and drawing from them in exchange plentiful merchandise and produce of the land, acquires an increased fund for the subsistence of its subjects.
The Dutch exchange their labour in navigation, fishing or manufactures principally with foreigners, for the products of their land. Otherwise Holland could not support of itself its population. England buys from abroad considerable amounts of timber, hemp and other materials or products of the soil and consumes much wine for which she pays in minerals, manufactures, etc. That saves the English a great quantity of the products of their soil. Without these advantages the people of England, on the footing of the expense of living there, could not be so numerous as they are. The coal mines save them several millions of acres of land which would otherwise be needed to grow timber.
But all these advantages are refinements and exceptional cases which I mention only incidentally. The natural and constant way of increasing population in a state is to find employment for the people there, and to make the land serve for the production of their means of support.
It is also a question outside of my subject whether it is better to have a great multitude of inhabitants, poor and badly provided, than a smaller number, much more at their ease: a million who consume the produce of 6 acres per head or 4 million who live on the product of an acre and a half.
