AGRICULTURE AND RURAL ECONOMY. 353 



over the pine forest during fourteen months was 33.1 inches ; 

 that over a sandy plain, at a distance of 1.9 miles, only 29.9. 

 Of that which fell on the forest only 18.6 inches reached 

 the ground. But through the influence of the trees, moss, 

 and fallen leaves, the evaporation was so decreased that the 

 forest soil retained a good deal more of the rainfall than 

 the open lands. Among the important general inferences 

 from these observations are that forests (l) tend to equalize 

 extremes of temperature ; (2) act as condensers of atmos- 

 pheric moisture, and hence (3) increase deposition of dew 

 on neighboring lands and (4) attract more rainfall ; (5) pre- 

 vent part of this from reaching the soil; (6) enable the soil 

 to retain much better what it does get, so that it has more 

 for future supply of springs and streams than the open land, 

 (7) and thus tend to prevent both floods and drouth. These 

 conclusions apply with especial force to evergreen forests. 

 The economy of nature in covering sandy and calcareous 

 regions with forests of pine thus becomes clearly apparent. 



THE SOIL IN ITS RELATIONS TO VEGETABLE PRODUCTION. 



Agricultural Geology. 



The science of agricultural geology, or, as some of its fol- 

 lowers prefer to term it, geognosy, has received a new 1 impe- 

 tus in the researches and publications of Professor Orth, of the 

 Agricultural Institute of the University of Berlin. Besides 

 his valuable prize essay ("Die Geognostisch-Agronomische 

 Kartirung ") Professor Orth has lately published a series of 

 six charts, each giving six diagrams in profile of the charac- 

 teristic sedimentary soils of North Germany. They show the 

 different strata of surface- and sub-soil, their thickness and 

 other characters, down to a depth of three meters about ten 

 feet. These, with the investigations upon which they are 

 based, illustrate most forcibly how incomplete a measure of 

 the value of a soil can be furnished by chemical analysis alone, 

 and how extended studies and observations are necessary to 

 a full knowledge of the factors that decide its fertility. 



New Jersey Marls. 



The annual report of the New Jersey Board of Agricult- 

 ure for 1876 devotes some eighty- four pages to a descrip- 



