DIFFICULTY OF' MEASUREMENT. Precise figures cannot be given, as the records of the ports of departure as well as those of arrival are not always to be had. From a statistical standpoint there are many obstacles to a perfectly accurate record, the chief being that of double counting. Emigrants return to their native land and again emigrate, which causes double counting at the ports of departure; while emigrants pass from one country into another, particularly from Canada to the United States, and this, together with the return of persons who have been in the country before, causes double counting at the points of arrival. These difficulties, which pre vent perfectly exact measurements, such as the calculation of an emigration rate for comparison with other phenomena of the population move ment, do not impeach the testimony of all available records as to the general growth of emigration. The emigration figures, so far as they are recorded in the European countries, are based upon such diverse elements that careful writers abstain from the attempt to make a total. Almost equally unsatisfactory for earn.
parative purposes are the records of the countries, which receive immigrants. Some notion of the volume of emigration from Europe can be gained from the fact that from 1841 to 1900 the rec ords of the United States show 18,527,516 ar rivals. Other regions received comparatively few immigrants until recent years. in 1870 the arrivals in the United States, 356.383, far ex ceeded those of Canada, Brazil, Argentina, Uru guay, and Australia combined, which according to the records of those countries amounted to 108,772 persons, while in 1S90 the arrivals in the United States, 495.021, were less than those of the five regions above named, 546,934. For later years figures are not available, as Canada has discontinued its statistics of immigration; but it may be stated in round numbers that from three-quarters of a million to one million of persons leave Europe annually for foreign lands, of whom about one-half come to the United States.