Aliens in transit are examined in the same manner as if desiring to remain in the United States, and if they are found to belong to the debarred classes they are refused permission to land. The head tax is charged on their account, as for other aliens, but it is refunded to the transportation company if the latter furnishes satisfactory proof that the alien has passed by a continuous journey through the territory of the United States, within thirty days, such proof to be furnished within sixty days after the arrival of the alien. Throughout the development of this body of laws certain well-marked tendencies can be traced. In the first place, the criteria of admission have steadily increased in severity, until now the law provides for the exclusion of practically every class of applicants who might fairly be considered undesirable, with the exception, perhaps, of illiterates. Secondly, we may note a tendency to concentrate all business, connected with the admission of aliens into this country or into membership in the nation, in the hands of a single branch of the federal government, and the increasing power and importance of this branch. Thirdly, there is manifest an increasing recognition of the right of this country to protect itself against unwelcome additions to its population, not only by refusing them admission, but by expelling them from the country, if their subsequent conduct proves them unworthy of retention. CHAPTER VII VOLUME AND RACIAL COMPOSITION OF THE IMMIGRATION STREAM As regards the volume of the immigration current the modern period has witnessed a continuation of the same general process which has been going on since 1820. The same succession of crests and depressions in the great wave has continued, the only difference being that the apex reached a much higher point than ever before. And, as in other periods, the great determining factor in the volume of immigration has been the economic situation in this country. Prosperity has always been attended by large immigration, hard times by the reverse. As already remarked, the year 1882 was marked by the largest annual immigration which had hitherto been recorded. The next low-water mark was reached in the middle nineties, following the depression of 1893. As the country recovered from this, immigration began to increase again, and rose almost steadily until in 1907 it reached the highest record which it has ever attained, a grand total of 1,285,349 immigrants in one year.[108] The crisis of that year interrupted the course of affairs, and immigration fell off sharply, and has not since completely recovered.