Ch. xiii. preceding Vkiv of Society. 521 



the progress of their population is checked by the 

 periodical, though irregular, returns of plagues 

 and sickly seasons. Dr. Short, in his curious 

 researches into bills of mortality, often uses the 

 expression — " terrible correctives of the redun- 

 dance of mankind ;" * and in a table of all the 

 plagues, pestilences and famines, of which he 

 could collect accounts, shews the constancy and 

 universality of their operation. 



The epidemical years in his table, or the years 

 in which the plague or some great and wasting 

 epidemic prevailed, (for smaller sickly seasons 

 seem not to be included,) are 431,-j" of which 32 

 were before the Christian aera/}; If we divide 

 therefore the years of the present aera by 399, it 

 will appear, that the periodical returns of such 

 epidemics, to some countries that we are ac- 

 quainted with, have been on an average only at 

 the interval of about 4-f years. 



Of the 254 great famines and dearths enume- 

 rated in the table, 15 were before the Christian 

 aera,§ beginning with that which occurred in Pa- 

 lestine, in the time of Abraham. If, subtracting 

 these 15, we divide the years of the present aera 

 by the remainder, it will appear that the average 

 interval between the visits of this dreadful scourge 

 has been only about ll years. 



* NewObserv. on Bills of Mortality, p. 96. 

 •f Hist, of Air, Seasons, &c. vol. ii. p. 366. 

 % Id. vol. ii. p. 202. 

 § Hist, of Air, Seasons, &c. vol. ii. p. 206. 



