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THE AMERICAN NATURALIST [Vol. XLVII 



the Wyville Thomson Ridge between the Faroe and Shetland 

 Islands are especially interesting. 



Other charts based upon the researches of Knudsen, Osten- 

 feld, and Brenneke show the distribution of dissolved oxygen in 

 the Atlantic down to 1,500 fathoms between 60° N. and 50° S. 

 latitude, proving that the higher the salinity and the tempera- 

 ture the less the absorption of oxygen, and hence the relative 

 deficiency of oxygen in the surface waters of the tropics. 



In a work of this magnitude there must needs be errors and 

 omissions, but these are so infrequent and of such small moment 

 that it seems ungracious to call attention to a few of the more 

 noticeable. The impalpable chalky deposit found in coral reef 

 regions is still referred to as "coral mud," although in 1910 

 Vaughan stated that it was a chemical precipitate, and this 

 enabled G. Harold Drew, of Cambridge, to demonstrate that it 

 is actually a precipitate caused by the action of a bacillus in 

 depriving the warm tropical water of its nitrogen, thus enabling 

 the calcium to combine with the dissolved C0 2 to form calcium 

 carbonate. 



In the table at the bottom of page 175, the statement "the 

 number of grams of salts per liter of sea water" should read 

 "the number of grams of salts per 1,000 grams of sea water." 



On page 187 "purifying sarcodic matter" should read "putri- 

 fying sarcodic matter." But such criticisms are really puerile, 

 and are given chiefly to show the negligible character of the 

 errors in the book, the editorial work upon which reflects great 

 credit upon Messrs. James Chumley and Dr. Caspari. 



A happy feature in the editorial arrangement of the book is 

 the system of marginal notes which enable one quickly to dis- 

 cover the subjects of each paragraph. One regrets the absence 

 of a bibliography, but the introduction of such a list would have 

 perhaps too greatly enlarged the size of the book. 



Apart from the purely scientific side which we have been con- 

 sidering the book indicates the possible practical value of these 

 studies. For example, it is shown that the growth-rate of pine 

 trees on the coast of Norway bears a direct relation to the tem- 

 perature of the ocean water, and for six successive years when 

 the amount of heat in the "Gulf Stream water" was great in the 

 month of May the air temperature in Norway was high in the 

 following winter. The water-temperature also bears a direct re- 

 lation to the time of the blossoming of Tussilago farfara at 

 Upsala. Also, Dr. Hjort shows that the southern limit of the 



