PREFACE. ix 



the distribution of living beings, and have of late 

 been brought into so great prominence by Dr. Car- 

 penter, 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 pro- 

 bably 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 



