Earth could not furnish Matter enough for all the Bodies that must Rise at the last Day, much less would the surface of the Earth furnish footing for so vast a Number; whereas we did (by the Method afore-mentioned) assert the Number of Men now living, and also of those that had dyed since the beginning of the World, and did withal shew, that half the
Rise, much less will the surface thereof (say they) afford footing to all those Bodies. Now ye assistances which I have given this good man are viz.
1°Supposing ye People in England, Scotland & Ireland to be abt nine Millions, Those in Holland and Zealand abt one Million, and in France 16, I say that by comparing ye rest of ye World therewth there are but between 300 & 400 Millions of Souls now living.
2°Upon this and Grant's Measures I ascertain ye Number that ever have died since ye Creation, & find that Munster would afford them all Graves, and ye Mangerton Bodies, or ye Equivalent in weight of Earth.
Having thus help'd my Friend, I took occasion to proceed, viz.
1stI find yt ye World being 5630 years old [Scaliger's Chronology, cf. p. 388, note 1], and Adam & Eve doubling but every 200 years (as Grant also saies) there must be now 316 Millions of People upon ye Earth; wch answers admirably, and is a brave Argument agst Scripture-Scoffers and Prœ-Adamites.
Nevertheless upon Examination of our Friend Grant's Positions,
2dlyI find People do double very differently in every Century of ye World, and have (as I think) rectitified his Doctrine, by making many Numbers in continuall Proportion.
3dlyI further find, that ye World at a Medium is at this day not much better peopled then our wretched Baronies in Keery, nor above 1⁄10 part so well as our poor Ireland is; nor above 1⁄100 part so well as Holland, wch is over-peopled.
4thlyI find yt in ye next 1400 years ye World doubling it's People in my corrected proportion, must be over-peopl'd, and then that there must be great Wars and Slaughters, and yt ye Strong must then destroy ye Weak, or ye World must (of necessity) come to an end.
5thlyI find by looking far back upon ye paucity of People in ye Asyrian, Persian, and other first Monarchies, how easy a thing 'twas for a few resolute Fellows to conquer ye World, as then it was. And that (whatever ye King of France may think) ye Universall or Great Monarchy does and will grow every Century more & more difficult by ye Course of Nature.
6thlyI conclude, that as People double faster now then they did in former Ages, so ye Rents of Lands must also rise proportionably, and ye number of years Purchase also: Wherefore let us get possession of what ye Affidavit saies is kept from us.
Thus, Dear Cosen (having ended where I began) I am still Yours.
[Endorsement] Dublin, Augt. 20th. 1681. A Copy of Sr. Wm. Petty's Letter to Sr. Robt. Southwell. Abt. ye Number of Mortals, &c.
Rawlinson MS. A. 178, ff. 71—72, Bodleian Library, among the Pepys papers. The letter has been printed in Rev. John Smith's Life, Journals, and Correspondence of Pepys (1844), ii. 317.
