190 HOAV CROPS FEED. 



acter of the latter determines to a certain degi-ee the na« 

 tnre of the atmospheric changes. In case of many crops, 

 the soil is but partially covered, and its peculiarities are 

 then of direct influence on its temperature. 

 Relation of Temperature to Color and Texture.— It 



is usually stated tliat black or dark-colored soils are sooner 

 "warmed by the sun's rays than those of lighter color, and 

 remain constantly of a higher temperature so long as the 

 sun acts on them. An elevation of several degrees in the 

 temperature of a light-colored soil may be caused by 

 strewing its surface with peat, charcoal powder, or vege- 

 table mould. To this influence may be partly ascribed 

 the following facts. Lampadius was able to ripen melons, 

 even in the coolest summers, in Freiberg, Saxony, by 

 strewing a coating of coal dust an inch deep over the sur- 

 face of the soil. In Belgium and on the Rhine, it is found 

 tliat the grape matures best, when the soil is covered with 

 fragments of black clay slate. 



According to Creuze-Latouche, the vineyards along the 

 river Loire grow either upon a light-colored calcareous 

 soil, or upon a dark red earth. These two kinds of soil 

 often alternate with each other within a little distance, 

 and the character of the wine produced on them is remark- 

 ably connected with the color of the earth. On the light- 

 colored soils only a weak, white wine can be raised to ad- 

 vantage, while on contiguous dark soils a strong claret of 

 fine quality is made. (Gasparin, Gours cT AgricultKre, 1, 

 103.) 



Girardin found in a scries of experiments ou the cultiva- 

 tion of potatoes, that the time of their ripening varied 

 eight to fourteen days, according to the color of the soil. 

 He found on August 25th, in a very dark humus soil, 

 twenty-six varieties ripe; in sandy soil, twenty; in clay, 

 nineteen; and in white lime soil, only sixteen. It is not 

 difticult, however, to indicate other causes that will at^ 

 count in part for the results of Girardin, 



