This book of Graunt's, although the first, is also one of the best that have been published on the sub ject. It contains many judicious observations on the imperfections of the bills, on the proportions of the deaths from different diseases and casualties, and on their increase and ' decrease with the probable causes of such fluctuations. He also observed, that " the more sickly the years are, the less fecund or fruitful of children also they be." Besides the London bills, he gave one for a coun try parish in Hampshire, in the first edition of his book ; and, in an appendix to the later editions, two others, one for Tiverton, the other for Cranbrook in Kent, with a few observations on foreign bills. He almbst always reasons justly from his data l but, as these were very imperfect, in his endeavours to draw more information from them than they could supply, he has sometimes fallen into error.
Even in this enlightened age, when a much greater proportion of the people devote a portion of their leisure to the acquisition of knowledge than in Graunt's time, subjects of this kind have but few at tractions for the generality even of reading men, who cannot endure the fatigue of thinking closely for any length of time. The author, accordingly, expected his readers to be rather select than nume rous, and was ambitious of that distinction, as ap pears by-the motto he prefixed to his work, Nos, me at miretur 7taba, laboro, Coate:atm pantie Lettoribus.
The book was, however, favourably received by the public, and went through five editions in fifteen years, the two first in 4to, the three others in 8vo; the last of them, published in 1676, two years after the author's death, was edited by his friend, Sir Wil liam Petty, who, in consequence of having sometimes spoken of this edition as his own, has by some writers been erroneously considered as the author..
Graunt's observations, like all others of a similar kind, by showing the usefulness of parish registers and bills of mortality, contributed to form a taste for these inquiries among thinking men ; and, conse quently, to improve both the registers and the bills derived from them ; so that, from his time, the sub ject has been continually cultivated more and more. Parish registers, in most parts of Europe, have been kept with more care ; and a succession of works of considerable merit have been published on the sub ject, containing an important part of the natural and political history of our species, and affording valua ble materials for the science of political economy.
The principal of these works we proceed to give. a short account of, in the order of their publica tion.
As the ages at which the deaths took place were not inserted in the London bills till 1728, Captain Graunt could not avail himself of that important in formation, but made a fruitless attempt to determine the law of mortality without it.
The Breslaw bills appear to have been the first wherein the ages at which the deaths took place were inserted, and the most important information which Bills of Mortality can afford, was first drawn from them by Dr Halley ; who, in 1692, constructed a ta ble of mortality for Breslaw from these bills for the five preceding years, and inserted a paper on the subject in the Philosophical Transactions, No. 196.
In 1699, Dr Davenant, in An Essay upon the pro bable Methods of making a People Gainers in the Reliance of Trade, published some extracts from Natural and Political Observations and Conclusions upon the State and Condition of England, by per mission of their author, Gregory King, Esq. Lancas ter lh:rald, who had completed them in 1696, though, they still remained in manuscript ; and the whole of this very curious production was published by Mr Chambers at the end of his Estimate in.1802. Mr King derived his information from the poll-books ; from actual observations in particular places ; from the assessments on marriages, births, and burials ; and from the parish registers. Many of his conclu sions agree surprisingly well, considering the time he wrote, with those which are the results of a hun dred years of further observations and inquiries.. He had access to much better data than Graunt, and his conclusions are more accurate; but he does not explain so fully how he arrived at them.
From the publication of Davenant's essay, above mentioned, nearly forty years had elapsed without any thing further being done in this way, when M. Kerseboom published an essay, in the Dutch lan guage, on the probable number of people in Holland and West Friesland, which he deduced from the Bills of Mortality (Hague, 1738, 4to) ; and twa others in 1740 and 1742: an account of the first of these three essays may be seen in the Philosophical Transactions, No. 450, and of the two others in 46&.
In 1742 was published the first edition of the ce lebrated work, entitled Die Gattliche Ordnung in den Veranderungen des menschlichen Geschlechts aus der Geburt, dem Tode and der Fortpflanzung desselben erwiesen von Johann Peter Siissmilch. The second edition appeared in 1761, enriched with the mate rials which had been laid before the public through various channels in the interim ; the third in 1765, and in 1775 a fourth edition of the two volumes of Siissmilch was published by Christian Jacob Bau-, mann, to which this editor himself' added, in 1776, a third volume, consisting of additions to the other two, and remarks upon them, with many new tables, and a copious index. The last edition of this work was published in 1798, but it does not appear to have been augmented or improved since 1776. It con tains long dissertations on every thing not mathe matical connected with the subject, and, besides original information, includes the substance of all the other publications on it previous to 1776; with an immense collection of materials, which, when borrowed, are often better arranged and render ed more convenient for reference, than they will be found to be in the works they were extracted from ; besides, the original sources of information are always referred to, and these advantages, with that of a full index, render it a valuable work for occasional reference. -The three thick 8vo volumes contain upwards of 2300 pages, closely printed with a small type, and the tables alone occupy 330 pages.