The THIRD ESSAY.
PRoofs that the number of People in the 134 Parishes of the London Bills of Mortality, without reference to other Cities, is about 696 thousand, viz.
I know but three ways of finding the same.
I. By the Houses, and Families, and Heads living in each.
2. By the number of Burials in healthfull times, and by the proportion of those that live, to those that die. |22|
3. By the number of those who die of the Plague in Pestilential years, in proportion to those that scape.
The First way.
To know the number of Houses I used three methods, viz.
1. The number of Houses which were burnt Anno 1666, which by authentick Report was 13200; next what proportion the People who dyed out of those Houses, bore to the whole; which I find Anno 1686, to be but 1⁄7 part, but Anno 1666 to be almost 1⁄5 from whence I infer the whole Housing of London |23| Anno 1666 to have been 66 thousand, then finding the Burials Anno 1666 to be to those of 1686 as 3 to 4, I pitch upon 88 thousand to be the number of Housing Anno 1686.
2. Those who have been employed in making the general Map[1] of London, set forth in the year 1682, told me that in
- ↑ Petty twice refers to a map of London "set forth in the year 1682" (see also p. 542), but no such map can be found at the British Museum. Mr C. H. Coote, of the Department of Maps, thinks it probable that the map which Petty used was Ogilby and Morgan's. This map was published with the title: A large and
