AGRICULTURAL TEXT-BOOK. 235 



ing to improvements, chiefly domical, each year in the manufacture. 

 (Ann. of Scien. Disc., vol. iv., p. 95.; Silliman s Journal, vol.xvi., N.S., 

 p. 275.) 



513. The Mangold can bo grown successfully for sugar-ex 

 traction at all places between 45 and 56 N. Lat. in Europe. 

 At Tobolsk, in Siberia, this crop is cultivated for food, but the 

 root is supposed to contain a smaller proportion of sugar than 

 than that raised farther south ; judging from the effect of a 

 warm climate on wheat, the nitrogenous matter should like 

 wise be smaller. The Sugar or Silesian Beet is more particu 

 lar as to climate, and consequently does not succeed so well in 

 general cultivation. (Prof. Wilson.) 



514. The root of this plant is not strictly a true root, but 

 a thick fleshy protuberance of the stem, to which the actual 

 roots are attached. The bulbous portion of some kinds of beet 

 is formed below the surface of the earth ; in others, it is above, 

 exposed to &quot;the air; and again, in some it is placed midway be 

 tween earth and air. Most varieties are spindle shaped ; some, 

 long and narrow, like the radish ; others thicker, and more round ; 

 some nearly square, with deep indentations ; and seldom flat 

 tened. The varieties are also distinguished by the leaves, curled 

 or smooth ; light or dark green ; fringed with red ; or entirely 

 red. 



515. If a root is cut across, it will be seen to be composed of 

 concentric zones or layers of fibrous vessels and cellular tissue 

 differing in color more or less according to variety. It will be 

 remarked, that tho leaf-stalks take their origin pretty deeply in 

 the body of the bulb, and there form an extensive region called 

 the heart, characterized by its greenish color and abundance of 

 fibrous vessels ; and, chemically, more analogous to the leafstalk 

 than to the rest of the bulb. The actual bulbous matter is dis 

 tributed in a zone about this heart, extending below it to the 

 point. The exterior, or skin, is composed of a peculiar compact 

 cellular substance, containing mineral and nitrogenous matter; 



