294 DESCRIPTIVE BOTANY. 



with 11,000 cuttings of new varieties. No report has thus far been made of 

 the comparative productiveness of the kinds introduced. 



A few years ago thirty-two varieties were sent from Mauritius to the British 

 West Indies ; about one half of these proved to be constant, and worthy of the 

 attention of sugar-growers. Besides these forms there are many others, which 

 are either sports or modifications, due to the effects of soil, climate, and mode 

 of culture. 



Chemistry. — Saccharose or cane-sugar yields to the chemist carbon, hydro- 

 gen, and oxygen, C12H22O11, and has a specific gravity of 1.60. It crystallizes 

 in prisms, which are phosphorescent when broken or electrified. Its solutions 

 turn polarized light to the right, and are hence called dextrose. It fuses at 

 .310° F. ; it is soluble in water, and slightly so in alcohol. 



Preparation. — Sugar is obtained by crushing the cane between grooved 

 rollers, whose grooves are armed with iron. The expressed juice is then 

 evaporated in pans at a low temperature and in a partial vacuum. By the 

 use of lime, charcoal, etc., it is refined. The drainings and uncrystallized 

 parts are molasses and syrup. 



The cane, after passing through the press, is soaked in water, and the strain- 

 ings and rougher parts of the molasses are mixed with the water ; then it is 

 allowed to ferment. It is then distilled, and produces rum. Large quantities 

 of sugar are obtained from the beet in Europe, and from the maple tree in 

 America. (See Beet, and Sugar Maple.) The sugar of China is obtained 

 from sorghum. 



Use. — Sugar is so well known that a description of its use would seem 

 superfluous. It is found on our tables in some form at every meal. It is a 

 perfect preservative for fruits of every description, and the principal ingre- 

 dient in all confectionery. In fact, few articles of food have attained so wide 

 a usefulness. 



Propagation . — To preserve the constancy of species and varieties, the cane 

 is propagated from cuttings either from the upper nodes of the culm or from 

 the rootstock. The new varieties are seedlings, though the plant seldom 

 matures seed in a .state of cultivation. 



SORGHUM, L. Spikelets panicled in twos* or threes on the spreading 

 branches ; the middle spikelet 2-flowercd, perfect, lower flower abor- 

 tive ; side spikelets sterile, without awns ; pedicels usually smooth. 

 Glumes leathery. Stamens 3. Annual. 



S. saccharatum, L. (Broom Corn.) (Andropogon saccharatum, Pers.) 

 Culm 6 to 9 feet liigh, solid, with pith intermingled with woody fiber like 

 Indian corn, about | of an inch in diameter. Leaves 1^ to 2\ feet long, Sc- 

 inches wade, lanceolate, acuminate, smooth, pubescent at the base ; panicle 

 2 feet long, branches simple or nearly so ; flexuous, rough, with short hairs. 



This plant is propagated from seed, hence it sports freely, ])roducing many 

 varieties. 



Geographij. — Sorghum grows best in the warmer parts of the temperate 

 zone, but will mature its seed in eastern Massachusetts. It is grown in south- 

 ern India, northern Africa, southern and middle Europe, and throughout the 

 United States of North America. 



Etymology. — The word sorghum is derivpd from sorghi, the Indian name of 

 this plant, the meaning of which is obscure. The common name, broom com, 



