These calculations extracted from very lame vouchers, shew how necessary it is to have authentic recapitulations: since, lame as they are, it is from these and the like, that Dr. Halley, and others, have calculated the value of annuities, which (at a time when all the states of Europe are borrowing money at the expence of every man’s private industry or property) ought to be valued at their real worth. Now, in all these calculations of mortality, it appears that what we have called the abuse of marriage or procreation is included. If it be true, as I think it is, from what I have seen and observed, that numbers, especially of children, among the lower classes, perish from the effects of indigence; either directly by want of food, or by diseases contracted gradually from the want of convenient ease; and that others perish for want of care, when the slightest assistance of a surgeon to let them blood, would be sufficient to preserve them against the inflammatory distempers to which they are chiefly exposed. If these things are so, must we not infer, that calculations formed upon a conclusion drawn from the births and deaths of mankind in general, cannot possibly be so exact as if the like were drawn from those of every class of inhabitants taken separately. It may here be answered, that among the rich and easy, there are found diseases which sweep off numbers, in as great a proportion as other distempers do of the poor: that we see very large families brought up among the lowest classes, while a great man has all the pains in the world to preserve a young boy from the wreck of a number of children. All this I agree may be true; but I should be glad to see in what proportion it _is_ so, and to be certain of the fact. I want to know the diseases of the rich and of the poor; I want to have as particular details of the births and deaths of every class, as I can have of those of the cities of Paris, London, or Breslaw. I want to know from what parents those multitudes of poor which I find every where are sprung; and most of all to have such accounts from different countries, where different manners prevail. For no just conclusion can be drawn from the comparison of facts, without examining circumstances. The most barren class in one country, may be the most fruitful in another. As an example of this, let any one compare the state of marriage among the footmen of London and of Paris.