Obfervations on Longevity. | 567 
vity than Breflaw, the Briti/h ftandard of life. At the firft pa- 
rh. in Hingham, in a period of fifty-four years, 2247 perfons 
have been born; there have been 521 marriages, and 1113 
deaths. Of me 168 have died in the firft year, and 404 un- 
der five years complete. Out of 1113 perfons who have died 
in 54 years in that parih, 84 períons have furvived 80 
years complete ; whereas at Breflaw ene, 34 out of 1000 fur- 
vived that age. 
. Thefe fpeculations are not defigned as a mere PEN ERP they © 
are intended for a valuable purpofe in civil life. The value of 
thofe eftates which are held for life, and the reverfion of them, 
can.only be determined by knowing the probability which there 
is, that their refpective holders will live for a longer or fhorter 
term-of y Lhofe-probabitities are different in different pe- ` 
riods of life. The prefent value of two eftates held in dower, 
whofe annual incomes are equal, may be very different. For 
inftance, a widow of 30 years of age has an equal chance of liv- 
ing, according to Dr. Halley's table, about 28 years; whereas 
one of 50 years has only an equal chance of living 17 years. - 
The prefent value, therefore, of the eftates held by them re- 
fpectively, as well as the value of their reverfon, though their 
annual incomes fhould be equal, are very different. . There has, 
as yet, been no certain rule eftablifhed - for eftimating the value 
of fuch eftates. . Whenever a widow has compounded with the 
heirs of an eftate for a fum of money in lieu of her dower, the 
compofition has been made at random, and not on any fixed 
principles that have determined it to be equitable. 
From the comparifon made above, it is evident, that the pre- 
fent value of eftates aniong us, held for life, and the value of the 
reverfion of fuch eftates, cannot be traced with accuracy from 
; the 
