I am well aware that the only perfectly trustworthy way of conducting the inquiry is by statistics derived from numerous life-histories, but I find it very difficult to procure these data.  I therefore have had recourse to an indirect method, based on a selection from the returns made at the census of 1871, which appears calculated to give a fair approximation to the truth.  My object is to find the number of adult male representatives in this generation, of 1000 adult males in the previous one, of rural and urban populations respectively.  The principle on which I have proceeded is this:—­

I find (A) the number of children of equal numbers of urban and of rural mothers.  The census schedules contain returns of the names and ages of the members of each “family,” by which word we are to understand those members who are alive and resident in the same house with their parents.  When the mothers are young, the children are necessarily very young, and nearly always (in at least those classes who are unable to send their children to boarding schools) live at home.  If, therefore, we limit our inquiries to the census “families” of young mothers, the results may be accepted as practically identical with those we should have obtained if we had direct means of ascertaining the number of their living children.  The limits of age of the mothers which I adopted in my selection were, 24 and 40 years.  Had I to begin the work afresh, I should prefer the period from 20 to 35, but I have reason to feel pretty well contented with my present data.  I correct the results thus far obtained on the following grounds:—­(B) the relative mortality of the two classes between childhood and maturity; (C) the relative mortality of the rural and urban mothers during childbearing ages; (D) their relative celibacy; and (E) the span of a rural and urban generation.  It will be shown that B is important, and C noteworthy, but that D and E may be disregarded.

In deciding on the districts to be investigated, it was important to choose well-marked specimens of urban and rural populations.  In the former, a town was wanted where there were various industries, and where the population was not increasing.  A town where only one industry was pursued would not be a fair sample, because the particular industry might be suspected of having a special influence, and a town that was increasing would have attracted numerous immigrants from the country, who are undistinguishable as such in the census returns.  Guided by these considerations, I selected Coventry, where silk weaving, watch-making, and other industries are carried on, and whose population had scarcely varied during the decade preceding the census of 1871.[25] It is an open town, in which the crowded alleys of larger places are not frequent.  Its urban peculiarities are therefore minimised, and its statistical returns would give a picture somewhat too favourable of the average condition of life in towns.  For specimens of rural districts, I chose small agricultural parishes in Warwickshire.