the distribution of living beings, and have of late been brought into so great prominence by Dr. Carpenter, that it has been impossible for me to avoid giving my earnest consideration to their general bearings on Physical Geography, and forming decided opinions, which, I regret to say, do not altogether coincide with those of Dr. Carpenter. The chief points on which my friend and I 'agree to differ' are discussed in the chapter on the Gulf-stream.
It was at first my intention that appendices should be added to the different chapters, containing lists and scientific descriptions of the animal forms which were observed. This it was found impossible to accomplish, chiefly on account of the large number of undescribed species which were placed in the hands of the experts who undertook the examination of the several groups. I am not sure that, even if it had been possible to furnish them in time, such lists would have been altogether an appropriate addition to what is intended merely as a popular preliminary sketch.
The metrical system of measurement, and the centigrade thermometer scale, have been adopted throughout the volume. The metrical system is probably familiar to most of my readers. In case the centigrade notation, which comes in very frequently owing to the frequent discussion of questions of the distribution of temperature, should not be equally familiar, a comparative scale, embodying those of
