246 WILLIAMS' CASE.—3 BLAND.

are proposed to be applied for information are altogether, or very
nearly similar to that for which they were made. Tables shewing
the expectation of life at different ages over the whole of Sweden,
for instance, could not be followed as safe guides for ascertaining
the expectation of life, at the same ages, over the whole of Hin-
dostan. And so too, it would be improper to take the tables of
expectation formed for the City of London as rules for ascertaining
the expectation of life in Wales. The causes materially affecting
the duration of human life, at the time and place for which a table
has been made, must, therefore, be understood and compared with
those of the place where the life in question exists, before such
allowances can be made for the differences, should there be any,
as will warrant the use of such table as a means of ascertaining
the value of each life.

But, as it is to those tables to which the modern English adjudi-
cations refer, in speaking of the means of ascertaining the pre-
sent value of a life interest, it will be proper to advert to some of
the principal circumstances of time and place from which the most
approved among them have been formed. It seems, that the for-
mation of tables of the expectation of life, at various ages, calcu-
lated from observations made, some time prior to the year 1679, at
Breslaw in Lower Silesia, as to the duration of human life, origi-
nated with Dr. Halley, of England. But it is now admitted, on
all hands, that those tables are so imperfect as to be wholly unfit
for use; thus leaving to the Doctor no other merit, in this respect,
than that of having been the first to shew the use of such tables,
and how they might be constructed from correct observations.
Rees' Cyclo. v. Life Annuities and Mortality. The next tables are
those which may be called the London tables, * formed by

233 Mr. Simpson from the bills of mortality for London for ten
years, from 1759 to 1768; and as these gave the values of lives
among a body of people taken, in the gross, in one of the worst
of all situations, they are by no means tit for common use; and are
therefore, now never resorted to as a means of ascertaining the
value of a life even in London itself. 1 Price Obser. 211; Rees'
Cyclo. v. Life Annuities and Mortality.

The next set of tables are those formed by Dr. Price from bills
of mortality kept in the parish of All Saints in the Town of North-
ampton in England, during the years 1735 to 1780. Northamp-
tion stands on a high region in the midst of England, and con-
tains at present about eight thousand four hundred inhabitants.
It is situated on the River Nen, and is chiefly built on the slope,
and near the top of a hill, and is generally clean and pleasant.
The parish of All Saints embraces about half the population of
the town. 2 Price Obser. 94. The next table is that which has
been formed for Carlisle, one of the most northerly towns of Eng-
land. The situation of Carlisle is extremely beautiful; it stands