[N]othing can be more improving to a young naturalist than a journey in distant countries. It both sharpens and partly allays that want and craving, which . . . A man experiences although every corporeal sense be fully satisfied. The excitement from the novelty of objects, and the chance of success, stimulate him to increased activity. Moreover, as a number of isolated facts soon become uninteresting, the habit of comparison leads to generalisation. On the other hand, as the traveler stays but a short time in each place, his descriptions must generally consist of mere sketches, instead of detailed observations. Hence arises, as I have found to m y cost, a constant tendency to fill up the wide gaps of knowledge by inaccurate and superficial hypotheses.Charles Darwin, The Voyage of the Beagle (London: John Murray, 1913 reprint ed., ch. XXI, p. 536
But I have too deeply enjoyed the voyage, not to recommend any naturalist, although he must not expect to be so fortunate in his companions as I have been, to take all chances, and to start, on travels by land if possible, if otherwise, on a long voyage.