The ten years from 186o to 1870 witnessed the operation of the first great factor which reduced the rate of national in crease, namely the Civil War. The superintendent of the ninth census, 1870, computed the effects of this cause—first, through direct losses, by wounds or disease, either in actual service of the army or navy, or in a brief term following discharge; secondly, through the retardation of the rate of increase in the coloured element due to the privations, exposures and excesses attendant upon emancipation ; thirdly, through the check given to immigra tion by the existence of the war; and finally, through the tem porary reduction of the birth-rate, due to the withdrawal of per haps one-fourth of the national militia during four years—to be a loss to the population of 1870 of approximately 2,515,000.
The rate of population increase declined steadily from 30.1% in the decade 1870-8o to 20.7% in the last decade of the century. From 1900 to 1910 there was a slight rise to 21%, due chiefly to a tremendous immigration of 8,202,388 in that decade, but in 1910-20 occurred an abrupt drop to 14.9%, the lowest rate of increase in the nation's history. This decline in rate of increase in the face of heavy immigration is explained chiefly by a decline in the rate of natural increase of native-born, a de cline so great that immigration could not wholly substitute for it. For the decade ending in 1930, however, there was an increase in population of 16.1% over the preceding census, the rate being a little higher than that of the preceding decade.
The causes of the decline in rate of natural increase have been the subject of much speculation by sociologists. It was not to be expected that the rate established from 1790 to 1830 by a virile and fertile race in a virgin land would continue. Gen. Francis A. Walker, superintendent of the 1870 and 188o censuses, upon no ticing that, in spite of increased immigration, the population in 186o was but io,000 more than if the rate of natural increase of 1830 had been maintained, ventured that the decline was due to the "competitive shock" of immigration, and that therefore immigration actually contributed little to the final total of popu lation but instead merely substituted foreign for native stock. It was no mere coincidence in his opinion that the birth-rate began to decline just as immigration began to increase, and that the decline was greatest where immigration was heaviest.
families are not so much of an economic asset now, even in rural areas, as they were in the early days, they are at least less of an economic burden on the farms, where there is still much work that can profitably be done by the growing boys and girls, than in the cities, where almost everything that is used or enjoyed must be paid for in cash. Further, the expansion of urban life has in general brought with it an increase in the cost of living, however that be measured, and has at the same time made possible (and widely desired) materially improved standards of living, and made available various forms of amusements and other individual activi ties and interests which compete with family life.
Other factors of some importance in explaining the decline in the birth rate include the growing tendency toward late marriages among the more ambitious and intellectual classes; the increased number of women who marry and continue in their gainful occupa tions after marriage; and in general the growing independence of women, the widening of their interests and their more frequent entrance into business pursuits. This last item may be over emphasized, however, since the percentage of women 15 years old and over in gainful occupations increased only from 18.9 in 1890 to 25.4 in 1910, and was even slightly smaller than this, namely, 24.8, in 193o. During the 4o-yr. period from 1890 to 1930, however, the percentage of married women gainfully em ployed considerably more than doubled, increasing from 4.6 in 1890 to 11.7 in 1930; and parallel with this change, the percent age of all gainfully employed women who were married increased from 13.9 in 1890 to 28.9 in 1930.
Despite the notable decrease in rate of growth, 1910-20, the actual numerical increase of 13,738,354 was greater than in any decade except 1900-10. Population increases showed a less defi nite geographical trend than ever before, the western movement having slackened decidedly, and seemed dependent instead upon industrial development.
Immigration distribution, for instance, had become more and more a matter of labour opportunities. The mountain and Pacific sections continued to have the highest rate of growth, but the percentages, when compared with those of the preceding decade, showed a sharp reduction. The only section showing a higher rate of increase than during the previous decade was the East North-Central division, comprising the States of Ohio, Indiana, Illinois, Michigan and Wisconsin, a section where also occurred the most noticeable industrial expansion.