WILLIAMS' CASE.—3 BLAND. 241

then value of the life estate, and deducting that value from the then
price of the inheritance, or the absolute or renewable estate. Some
such proportional valuation must have been made in each of these
cases, as well as in those which relate to the discharge of mortgages,
or other incumbrances; yet there is nothing to be found in the reports
of any of them, or in the reports of those which involve the apportion-
ment of incumbrances, or in those which relate to the abatement of
specific legacies or to the adjustment of the amount for which an an-
nuitant is to be admitted as a creditor against the estate of a
bankrupt or insohent, before the year 1750; which-alludes to any
positive rule of apportionment, or that indicates the principles by
which the Court was governed in putting a present value upon a
*life estate of any sort, or of apportioning any burthen be-

tween such an estate and a remainder or reversion depend- 227
ent upon it. Ryle v. Brown, 6 Excli. Hep. 265; Darley v. Singleton,
6 Exch. Rep. 426.

The putting of a present value upon a life annuity, or upon a
certain rent for life, or upon a specified annual life income of any
description necessarily involves a consideration of the chances of
life of the individual during whose life such an annual income is
claimed; for although other matters must be taken into considera-
tion in making an estimate of its present value; such as the suffi-
ciency of the security, the probable punctuality of the annual pay-
ment, the general demand for the use of money, and the like; yet,
it would be difficult to make any calculation as to the duration of

a single life without the aid of some general observations as to
the rate of mortality, and the probable duration of such lives in
like situations. But a judicial controversy as to the present value
of a particular life interest, being, in its nature, confined to an in-
sulated subject, however dependent a full understanding and cor-
rect determination of it may be upon the doctrine of chances,
cannot afford the means of collecting those facts and circum-
stances on which that doctrine rests, since the doctrine is itself
the result of general observations upon those previously collected
facts and circumstances, in relation to the duration of human life,
whilst the adjudication must necessarily be, if it proceeds upon
that doctrine at all, a mere application of it to the peculiar case.
Hence it is, that, although judicial investigations may, in such
cases, be greatly facilitated by a just application of that doctrine,
there is no allusion to any rule for estimating the probable con-
tinuance of life to be met with, in any of the reported adjudica-
tions, until long after the publication of several essays upon the
doctrine of chances in relation to the duration of human life.

Doctor Edmund Halley, an eminent mathematician of England,

appears to have been the first who undertook to explain the doc-

taine of chances in relation to the probable duration of human

life. About the year 1690, he published his Essay on the Deter -

16 3B.