496 PHILOSOPHICAL TBANSACTIONS. [aNNO 1774. 



the alkali neutralized too great a portion of the acid. All these writings having 

 been now exposed 6 months to the air, in N° 5 and 6 the blackness is quite 

 destroyed; N'^ 4 is somewhat faded; N° ], 2, 3, remain nearly as they were; 

 N° 2 and 3 being still superior to the standard. 



F'. Observations on the State of Population in Manchester, and other adjacent 

 Places. By Dr. Percival. p. 54. 



Reprinted in this author's collected works, recently published (1807) in 4 vols. 

 8vo. by his son. 



VI. Observations on the Bill of Mortality, in Chester, for the year 1772. By 



Dr. Hay garth, p. Qj . 



A writer, of distinguished abilities in political arithmetic, has offered many 

 arguments, which give cause to apprehend that England, in about 70 years, has 

 lost near a quarter of her people. Accurate registers of mortality, with other 

 collateral inquiries, can, with most certainty,, confirm or confute this opinion, 

 and determine a question of the most striking importance to our very existence 

 as a nation. The doctrine of annuities for widows, and other persons in old age, 

 the value of reversionary payments, and of assurances on lives, and other im- 

 portant questions in civil society, can only be determined by faithful registers, 

 showing the duration of human life, in various situations of town and country. 

 The slightest view of tables of mortality show, how erroneous every calculation 

 relating to this subject must be, drawn from the London bills, or perhaps those 

 of most other considerable towns, and applied to the inhabitants of this city. 



Chester is healthy to an uncommon degree, when compared with towns of 

 the same size. Various circumstances, which contribute to render this place so 

 remarkably salubrious, might be pointed out; but it can here be only observed 

 in general, that this salutary effect may, with great probability, be chiefly attri- 

 buted to the dry situation, clear air, pure water, and general temperance of the 

 people. In August 1772, the inhabitants of St. Michael's, one of the g parishes 

 into which Chester is divided, and situated in the very centre of the city, were 

 numbered with great accuracy : in this parish were 151 families, 127 houses, 

 6l8 inhabitants, 246 males, 372 females, l66 married, 41 widows, 21 widowers, 

 and 137 children under 15 years old. Hence the number of persons, never 

 married above 15, is 253. From this account also it appears, that near 4|- per- 

 sons dwell in each house; that the proportion of females to males is as 62 to 41, 

 or nearly as 3 to 2 ; that the widows are to the widowers nearly as 2 to 1 ; that 

 the number married is little more than one quarter of the inhabitants : the com- 

 mon proportion of married people is about ^ of the whole. The number of 

 christenings, at St. Michael's, for the last 10 years, are 147, or 14.7 yearly; 



