Age.—The characteristics of a population from the point of view of age, which German writers term “Altersaufbau” can only be treated very generally. Table V. on p. 514 is quoted by Haushofer (p. 213) from Von Scheel’s Handbuch der Statistik.
This “age scale” shows us the proportion in which persons of various categories of age are found combined to form populations. The general characteristics of the groups are tolerably obvious. It must be remembered that after thirty years the periods are decennial. The difference between the age scale of Europe and that of North America is considerable. In the latter, owing mainly to the fact that emigrants are usually young, a much larger proportion of the population than in Europe are under thirty years of age. On the other hand the age scale of France presents a feature of an opposite kind, namely, a deficiency of persons under fifteen years of age, and an excess of those over forty, as compared with the average of Europe. This conformation of the age scale may be compared with that of Hungary, where the number of children is larger and the number of persons over forty less than the average. It is probable that the smaller number of children in the one case and the larger in the other directly lead respectively to a smaller infant mortality in France than in Hungary. As M. Block observes (Traité, p. 409), “Nous avons moins d’enfants; mais, grâce à une moindre mortalité dans le jeune age, nous avons plus d’adults.” It is obvious that cæteris paribus it is easier to pay the requisite attention to the rearing of a small number of children than to do the same for a larger number.
Careful inquiries into age scales are of very recent origin, the data required for evaluating those relating to earlier periods being absent. Moreover, erroneous statements as to their age are made by a much larger number of persons than might be supposed, sometimes from carelessness or ignorance, but also intentionally. The tendency of women over twenty-five to understate their age, combined with overstatements of age by girls and young women under twenty, always tends to make the twenty to twenty-five section of the age scale unduly large (see Census of England and Wales, 1881, vol. iv., “General Report”). We must regard even the age scales now in existence as merely first approximations, for it is evident that observations obtained from several censuses must be reduced and combined before we can feel certain that accidental causes of error have been eliminated. This is all the more necessary as the age scale of any given population cannot be regarded as fixed, any more than the magnitude of the population itself, both being liable to modifications arising out of the varying dynamical conditions existing at different periods. And this brings us to the second portion of our inquiry, in which we shall indicate in the most general way the nature of the proximate causes which underlie the phenomena of population considered as a fact existing at a particular moment of time.
II. Population, dynamically considered, is the result of two pairs of opposing forces, whose combined action may, for convenience, be theoretically conceived of as balancing each other, but which never do so balance as a matter of fact. A comparison of two successive censuses invariably shows some “movement of population.” In nearly all civilized countries the movement shown is one of growth when the body of population examined is large. The population of a village or a small town may, quite conceivably, show a reduction in number for the period between two censuses, but this can hardly be the case with a large town, and still less with a nation, unless as the consequence of some great calamity such as an earthquake or a pestilence or a change in the climatic or economic conditions of the country inhabited. A great war, of course, produces a certain retardation of the rate of increase. Although some of the uncivilized peoples of the world are rapidly disappearing, the tendency of the population of the whole world is evidently to increase—at what rate it is impossible to say, for reasons already mentioned; and our inquiry will, therefore, be confined to peoples regarding whose population we have comparatively accurate information for an adequate number of years.
The causes of the movement of population are internal and external. The internal arise out of the numerical relation between the births and deaths of a given period, there being an increase when there are more births than deaths, a decrease in the contrary case. Haushofer expresses this by a formula which is sometimes convenient:—“There is an increase where the intervals between successive births are smaller than those between successive deaths” (p. 115). The external are immigration and emigration. The intensity of these two forces operating on population depends on a variety of causes, into which we do not propose to enter. Generally speaking, it may be said that “new” countries, where the density of population is small, attract immigrants from countries in which the density of population is great. The density of population is expressed by the figure denoting the number of inhabitants per square mile (or square kilometre) of the territory they occupy. For a discussion of the various political, social, and economic causes which determine density of population, we must refer our readers to the works of Haushofer (p. 173) and Block (p. 456). Before analysing the components of the movement of population it will be useful to examine briefly that movement itself, and ascertain what is its normal rate in civilized countries. The mode of expressing this rate which is most commonly adopted in the exposition of statistics of population is to state the number of years in which a given population “doubles itself.” It is not a very scientific method of expressing the facts, since it assumes that the rate of a few years will continue for a period of many years, but, in deference to custom, we give a table constructed in accordance with it.
| Basis of Calculation. | Approximate Doubling Years. | ||
| Years. | Annual Percentage of Increase. | ||
| Norway | 1845–55 | 1·15 | 61 |
| Denmark | 1845–55 | 0·89 | 71 |
| Sweden | 1850–55 | 0·88 | 79 |
| Saxony | 1852–55 | 0·84 | 83 |
| Holland | 1840–49 | 0·67 | 103 |
| Sardinia | 1838–48 | 0·58 | 119 |
| Prussia | 1852–55 | 0·53 | 131 |
| Belgium | 1846–56 | 0·44 | 158 |
| Great Britain | 1841–51 | 0·23 | 302 |
| Austria | 1842–50 | 0·18 | 385 |
| France | 1851–56 | 0·14 | 405 |
| Hanover | 1852–55 | 0·002 | 3,152 |
