Periodical Literature. 423 



since they contribute less to the moisture contents of the air 

 than crops or forests and lose considerable water by surface run- 

 off must be drained." 



On sandy soils forest cover is needed to evaporate the water, 

 which otherwise would percolate and run off in subdrainage; 

 similarly on steep slopes and rocky ground to prevent rapid runoflF. 

 If clearing is a necessity, intense cultivation should follow as, af- 

 ter forest it is field crops which contribute most moisture to 

 the air. 



"The effect of forests upon climate, if viewed as a local in- 

 fluence, must necessarily be insignificant." (This seems a 

 strange corollary, for the efifect felt at a distance must necessarily 

 be even greater nearby. — Rev.) 



The author concludes with a disparagement of local observa- 

 tions to solve the problem of influence on climate, which can only 

 be solved "by rising mentally to a height which opens wide per- 

 spectives both to the distant shores of the Gulf of Mexico and 

 of the Atlantic Ocean and to the most interior portions of the 

 continent." B. E- F. 



The relation of Forests in the Atlantic Plain to the Humidity af the 

 Central States and Prairie Region. Science, July, 1913. Pp. 63-75. 



The noted Russian investigator, Tkat- 

 Forest chenko, has studied the influence on soil 



Influence conditions of plantations 35 to 40 years old, 



on made on black humose farm soil with larch, 



Soil. spruce and oak. The depth of the humus 



layer has decreased and correspondingly 

 the transition zone from humus to underlying loess increased ; 

 the loess soil has, however, been studded with brown humus de- 

 posits ; the granular structure in the lower two layers has in- 

 creased, the gravelly formations are observed in all three layers; 

 a nutlike structure is found in the middle layer of the humus 

 zone in dry weather, especially in the oak plantation. 



As regards moisture condition, the interesting discover}'- was 

 made that in a field lying waste for years the upper layer of 22 

 feet was drier than the forest soil, but below this layer the re- 

 rerse was true. Those parts of the loess zone from which the 

 carbonates were leached possessed the greatest humidity, while 



