ANNOTATIONS AND ADDITIONS. 123 



The plains which border the Icy Sea are the domain of 

 cryptogamous plants. They are called Tundras (Tuntur in 

 Finnish) : they are swampy districts extending farther than 

 the eye can reach, partly covered with a thick carpet of 

 Sphagnum palustre and other mosses, and partly with a dry 

 snow-white covering of Cenomyce rangiferina (Eein-deer 

 moss), Stereocaulon paschale, and other lichens. Admiral 

 Wrangell, in describing his perilous expedition to the new 

 Siberian islands so rich in fossil wood, says : " These Tun- 

 dras accompanied me to the extreme arctic coast. Their 

 soil has been frozen for thousands of years. In the dreary 

 uniformity of landscape, the eye of the traveller, surrounded 

 by rein-deer moss, dwells with pleasure on the smallest patch 

 of green turf showing itself now and then on a moist 

 spot." 



( 18 ) p. 8. " The causes which lessen both heat and 

 dryness in the New World" 



I have tried to bring together in a brief and compendious 

 manner the various causes which produce greater moisture 

 and a less degree of heat in America ; it will of course be 

 understood that the question respects the general hygrome- 

 tric state of the atmosphere, and the temperature of the New 

 Continent as a whole. Single districts, such as the island of 

 Margarita, the Coasts of Cumana and Goro, are as hot and as 

 dry as any part of Africa. It must also be remarked that 

 the maximum of heat at certain hours of a summer's day has 

 been found, on a series of years, to be almost equal at very 

 different parts of the earth's surface, on the Neva, the Senegal, 

 the Ganges, and the Orinoco ; being approximately between 



