COXCLUDIXG REMARKS. 597 



it. I had lived in the cabin three years and a half and had got 

 to look upon it as a home. 



After a voyage all over the world, there is nothing which is so 

 much impressed upon the mind as the smallness of the earth's 

 surface. We are apt to regard certain animals as fixed and 

 stationary, and to contrast strongly with their condition that of 

 forms possessing powers of active locomotion. In reality we are 

 as securely fixed by the force of gravity as is the Sea Anemone 

 by its base ; we can only revolve as it were at the end of our 

 stalk, which we can lengthen or shorten only for a few miles' 

 distance. We live in the depths of the atmosphere as deep-sea 

 animals live in the depths of the sea. We can, like these, crawl 

 up into the shallows or we can occasionally mount at peril in a 

 balloon ; but the utmost extent of our vertical range is a distance 

 no greater than that which we can walk in a couple of hours 

 horizontally on the earth's surface. 



The " Challenger " travelled on the voyage from Portsmouth 

 and back to the same port, 68,690 miles, and this distance, taking 

 into consideration the time consumed from port to port, was 

 traversed at the average pace of only four miles an hour, or fast 

 walking pace. In an express train on land the entire distance 

 could be conceived of as being accomplished in eight weeks, and 

 at the rate at which a Swallow can fly in about half that time. 



If there were land all along the equator it would be possible 

 to run round the world in a train in less than three weeks. I 

 used to wonder how the main mass of the inhabitants of America 

 could have peopled the entire country down to Cape Horn, from 

 so remote a starting-point as Behring's Straits ; but a walk of 

 four miles a-day would bring a man from Behring's Straits to 

 Cape Horn in about seven years, and a move of a quarter of a 

 mile a-day would bring a tribe the same distance in a little over 

 a century. 



The earth, considered as a comparatively insignificant com- 

 ponent particle of the universe, may be justly compared to a 

 small isolated island on its own surface. As, in the course 

 of ages, such an island developes its own peculiar insular fauna 

 and flora, so probably on the surface of the earth alone has 

 the peculiarly complex development of the element Nitrogen 



