The explanation is as follows :—Of 10,000 infants born at Carlisle, 1539 would die in their first year, and 8461 would survive, while 4000 would live to 56 and upwards. In the Equitable Table, of 3022 persons attaining the age of 40, 43 and 44 die in the two succeeding years, leaving 3S35 surviving at their 42nd birthday.
Of the three species of tables, this is the most useful for mathe matical deduction, and the least adapted for a comparative view. The best way of using them for the examination of their relative bearings is to compare the probable life, as it is called, of the two, that is, the time in which the numbers living are reduced one-half. Thus taking the age of 31, we see that the numbers living in the Northampton table are halved at the age of 59, while in the Carlisle table this does not happen till the age of 67.
Thus of 10,000 persons attaining the age of 40, 130 die in the following year according to the Carlisle tables ; while of 10,000 who attain the age of 41, 138 die in the next year. This species of table is the only one of the three which is immediately applicable to the comparison of two sets of data at and near a given age ; while the one to which we now come serves to compare the total character of two sets of data from and after a given age. It also unites the fluctuations of different years, by compensation : thus looking at tables II. we should hardly suspect that closeness of resemblance between the Carlisle and Equitable tables, in the value of life, which is obvious in those marked III. • To avoid decimal points, 100 persons are supposed at each age : thus, 100 persons aged thirty enjoy among them 3086 years, according to the Friendly Societies' tables, or each of them, on the average, 30'86 years. This sort of table is much the best for a running comparison of two laws of mortality.
It must be observed that the two first of the preceding sets of tables attempt a degree of minuteness which cannot be supposed to be attainable with existing data. To distinguish between the decrements of two successive years, and the percentages of the two sets of deaths, would require much greater numbers of living at the two ages than ever have been found in the materials of a table. Nor is the regularity observable in these tables also observable in the observations which produced them; this result being obtained by hypothetical adjust ments, so as to attain the nearest representation, in the main, of the materials under investigation. This applies particularly to the old lives, which are but few in number, and present various diversities of fluctuation. Almost all the tables which have been constructed present some general results of utility; and we cannot but think that writers on this subject, by attending too much to minute comparison, and not enough to general indications, have not made all the legitimate deductions which the materials before them would have afforded. We
proceed to some general account of the state of mortality, restricting ourselves to the last and present centuries, to life in England only, and to the general variations of mortality and the relative mortality of the sexes.
The circumstance which must strike every one as most remarkable, is the great increase which has taken place in longevity. To put this in a clearer light, we shall collect various tables of the mean duration of life, specifying the epochs of their collection. The tables formed from male lives only, have a capital letter ; from female lives only, a small letter; from both, a capital and a small letter. At the bottom of each table is given the period in which all or most of the lives became extinct. The number in the table is the number of years enjoyed by ten individuals : thus in table T, at the age of 20, the mean duration of a single life is the tenth part of 293 years, or 29'3 years.
Comparing tables made from the same sex, or from the mixture of both, that is, looking at T, n, A, E, and o together for the males (F and F are made from the labouring classes exclusively), at t, r, and g for females, and at L I, It h, r n, and c e for both together, the general increase of longevity is sufficiently apparent. The older tables, made from burial-registers, will not prove more than the general fact, uncorrected as they aro both for increase of population and migration. The great excess of the Carlisle Table, it must be remembered, is partly owing to the deaths from small-pox having been allowed for, which, though necessary in a table intended for subsequent use among a vaccinated population, prevents the comparison betweeu the Carlisle and preceding tables from being altogether fair. The tables A and F are very similar, and show that the life of the more provident class of labourers (who resort to Friendly Societies) is now as good as those of the Amicable Insurance Office in the last century. That Society is supposed not to have been, in former times, so careful in the selection of lives as the modern institutions of the same kind. This was probably the case, though another circumstance may have operated still more on the table. Up to the year 1808, or thereabouts, no lives older than 45 were taken ; so that, while the registers of the Equitable Society have been constantly recruited with selected lives from 45 to 60, as well as at the lower ages, those of the Amicable Society have not had the same advantage above the age of 45. We think however that much of the difference between the two arises from the earlier period which the tables of the latter Society represent.