THE SCIENTIFIC MOTIVE
Although purely scientific curiosity became an important element of travel only toward the end of the eighteenth century, there were in earlier times a few for whom this was a great incentive. To seek for knowledge for its own sake, to be fired with the desire to extend, if only by a little, the limits of the known, is not wholly a modern trait; but before this could be in large measure an important factor, the extraordinary widening and development of scientific interest characteristic of the last century and a half was necessary. Each has, however, contributed to the advance of the other, and the vast additions to knowledge gained by scientific exploration have in large degree provided the materials from which the present structure of science has been built. As once for religion, so now for science men plunge into the unknown; now as then they strive, not for themselves, but for an ideal.
Travel is then, as we have seen, as old as the human race, and of travelers there are and have been many kinds, according to the motives which induced them to fare forth. The records of these many travelers form a body of literature whose interest is undying, for besides the facts which they have gathered, and the additions to our knowledge which they have made, they give us often a clear and vivid picture of the character of the travelers themselves, their courage in the face of danger, their patience in overcoming every kind of obstacle; and heroism and self-sacrifice of the truest and highest types have been exemplified again and again in their lives. Of all these many travelers but a part have left a record, and, as might be expected, the earlier have left far less than those of later times. From the historical point of view, the records fall into several fairly definite groups or periods, each differing from the other not only in time, but also to a considerable extent in the character of the motive which was dominant.