VOL. XLII.] PHILOSOPHICAL TRANSACTIONS. • G'iQ 



to be cited and proved) he gives the chief observations he was able to obtain ; 

 and believes that these, joined with those contained in his first treatise, will be 

 a sufficient proof of his general calculations. 



Mr. Kersseboom then gives an account how many people were buried in the 

 city of Dort every year, from 170O to 1739 inclusive, amounting, in 40 years, 

 to 28977 persons ; which is annually, on an average, 724. — ^The marriages are 

 202 couple annually, during the same time, which should produce (according 

 to the author's calculations in his first treatise) 325 children per 100 marriages, 

 and consequently 656 children per annum ; but he has found it, on an average, 

 to be 651. — This city being a sea-port, and driving a large trade to Scotland, 

 and on the Rhine, and consequently many of the people, whose traffic brings 

 them to Dort, may die there, it is supposed, that about 680 children are bor» 

 annually there, and that consequently this city may contain 24000 souls. 



Next to this, the author gives an account of Haerlem, how many people died 

 there in 84 years, from 1656 to 17 39 inclusive, namely, 132 1 32 persons, 

 which is annvially, on an average, 1573. — The next is, how many marriages, from 

 anno 169O to I739 inclusive, namely, 2191O, is annually 438, on an average. 

 — As to the births, Mr. Kersseboom refers to his first treatise, p. 54, where he 

 supposes, that 1450 children may be born alive annually; and endeavours to 

 demonstrate it further, by giving an account of the births for 60 years, namely, 

 from 168O to 1739, and finds it to be 1453 ; from which it is calculated, that 

 this city contains 50500 souls, as mentioned in his first treatise. 



The next account is that of the burials of Delft and Delftshaven, from the 

 years 1724 to 1739, being 15 years, and is found to be annually, on an average, 

 723 persons ; but there is subjoined, for the greater certainty, an account from 

 the year 1696 to 1739, which proves it to be 748 persons annually. 



The marriages are, in the same time of 44 years, on an average, 224 per 

 annum, which should produce 728 children, according to the rule laid down 

 before, namely, 100 marriages producing 325 children; but is found to produce 

 from 1690 to 1739 inclusive, to be 648 per annum, on an average; from 

 whence it is supposed those two places contain 25000 souls. 



The city of Leyden comes next in consideration. It appears by a list for 50 

 years, namely, from the year 1690 to 1739 inclusive, that there have been 

 buried in that city annually, on an average, 1919 persons ; and married during 

 the same time, annually, on an average, 558 couple, which, agreeable to the 

 former rule, would produce 1813 children per annum, but is found to have 

 been 1834 per annum, on a medium, as aforesaid ; the author concludes con- 

 sequently, that this city contains 63000 souls. 



The next city is Amsterdam : it appears by a list, that since the year i6q6 to 



