It has long been observed that in Europe the marriage rate falls in hard times and rises again on the return of prosperity. "According to all experience," declares Mill, "a great increase invariably takes place in the number of marriages in seasons of cheap food and full employment."[760] The middle and upper classes, says Fawcett, "do not often marry unless they have reasonable prospect of being able to bring up a family in a state of social comfort.... But the laborers, who form the majority of the population, are but slightly influenced by such cautious foresight. Even a trifling temporary improvement in their material prosperity acts as a powerful impulse to induce them to marry; for it is a demonstrated statistical fact that the number of marriages invariably increases with the decline in the price of bread."[761] Farr and Bodio reach the same conclusion.[762] Ogle on the other hand, while agreeing entirely with these writers as to the favoring influence of prosperity and the depressing effect of hard times on the number of marriages, finds in England, so far as the price of bread alone is concerned, that the reverse is true, more marriages there taking place among the laboring class when bread is dear. In this case, he urges, the higher cost of bread may itself be an incident of increased industrial activity, depending in part on the rise of freight charges on imported wheat. So he concludes that "the marriage rate rises and falls with the amount of industrial employment, which in its turn is determined by the briskness of trade, as measured by the values of exports, which also rise and fall concomitantly, and produce by their effect upon freights a simultaneous rise or fall in the price of wheat."[763] The researches of Oettingen, Bertillon, and especially those of Cauderlier, have also disclosed a general variation in the marriage rate corresponding with the rise or fall in the price of the necessaries of life.[764] War in particular has a powerful influence in lowering the marriage rate, while on the restoration of peace the loss may be largely or entirely recovered. "In 1864 Denmark was at war with Prussia, and its marriage rate fell from 15.0 to 11.13" for each 1,000 inhabitants, "the lowest point it has ever yet reached, but in the next year, the war being over, rose to 17.8, and was higher than it has ever been again. In 1866 Austria was at war with Prussia, and, while the Prussian rate fell from 18.2 to 15.6, the Austrian rate fell from 15.5 to 13.0, but on the cessation of hostilities rose in 1867 to 19.3, a higher level than in any earlier year."[765] According to Willcox,[766] the same rule appears to hold good in the United States. In Massachusetts for the period 1850-90 the marriage rate was low in the years of industrial depression and during the Civil War. Furthermore, the same writer has for the first time demonstrated that the average divorce rate for the whole country is