12 



THE IRKIGATION AGE. 



same as water, being oxygen and hydrogen, with an 

 equal quantity of carbon added. 



Under the microscope this woody fiber appears to 

 consist of what is called "cellular" matter, the true 

 woody fiber, and a coating for strengthening purposes, 

 called "incrusting" matter. This cellular matter is 

 composed of oxygen and hydrogen in the proportions 

 to form water, but it is difficult to separate them to de- 

 termine the elementary construction, but we shall see 

 that they demand a certain food and are intended 

 for an important purpose. 



The woody fiber sometimes constitutes a large pro 

 portion of the" plant, and sometimes it is very small. 

 In grasses and corn growing plants, it forms nearly 

 one-half of the weight, but in roots and in plants used 

 for food it is very small in the first stages of their 

 growth. The following table gives the percentage of 

 woody fiber in a few common plants while in a green 



Name of plant. Per cent of woody fiber. Water. 



Pea stalks 10-33 



White turnips 3.0 



Common beet 3 - 



Red clover 7.0 



White clover ^ 4.5 81.0 



Alfalfa in flower 9-0 



Rye 1-0 68.0 



STARCH. 



Next to woody fiber, starch is the most abundant 

 product of vegetation. By whatever names the various 

 kinds of starch are called: wheat starclh sago, potato 

 starch, arrow root, tapioca, cassava, etc., they are all 

 alike in their chemical constitution. They will keep 

 for any length of time when dry and in a dry place, 

 without any change. They are insoluble in cold water 

 or alcohol, but dissolve readily in boiling water, giv- 

 ing a solution which becomes a jelly when cold. In 

 a cold solution of iodine they assume a blue color. 



The constituents of starch are carbon, oxygen, and 

 hydrogen, with less carbon and more oxygen than woody 

 fiber and about the same quantity of hydrogen. 



That starch constitutes a large portion of the 

 weight of grains and roots usually grown for food the 

 following table will show, one hundred pounds being 

 the quantity upon which to base the percentage: 

 Name of plant. Percentage of starch. 



Wheat flour 39.77 



Rye flour 50.61 



Barley flour 67.70 



Oatmeal 70.80 



Rice 84.85 



Corn : 77.80 



Buckwheat 52.0 



Pea and bean meal 43.0 



Potatoes 15.0 



In roots abounding in sugar, as the beet, turnip, 

 and carrot, only two or three per centum of starch 

 can be detected. It is found deposited among the 

 woody fiber of certain trees, as in that of the willow, 

 and in the inner bark of others, as the beech and the 

 pine. This is the reason why the branch of a willow 

 takes root and sprouts readily, and why the inner bark 

 of certain trees are used for food in times of famine. 



GUM. 



Many varieties of gum occur in nature, all of them 

 insoluble in alcohol, but become jelly in hot or cold 



water, and give a glutinous solution which may lx v 

 used as an adhesive paste. Gum Arabic, or Senegal, 

 is the best known. It is produced largely from the 

 acacia, which grows in Asia, Africa. California and in 

 the warm regions of America generally. It exudes from 

 the twigs and stems of these trees, and forms round, 

 transparent drops, ofr "tears." May of our fruit trees 

 also produce it in smaller quantities, such as the apple, 

 plum and cherry. It is present in the malva, or althea, 

 and in the common marsh mallow, and exists in flax, 

 rape, and numerous other seeds, which, treated with 

 boiling water give mucilaginous solutions. 



All the vegetable gums possess the same chemical 

 constituents of carbon, oxygen, and hydrogen, in nearly 

 the same proportions as woody fiber and starch. 

 SUGARS. 



All sugars may be classified according to four prom- 

 inent varieties : Cane, grape, manna and glucose. 



First Cane sugar is so called from the sweet sub- 

 stance obtained from sugar cane. It is also found in 

 many trees, plants and roots. The juice of the maple 

 tree may be boiled down into sugar, and in the Cau- 

 casus the juice of the walnut tree is extracted for the 

 &amc purpose. 



It is also present in the juice of the beet, turnip 

 and carrot. Sugar beet cultivation is assuming enor- 

 mous proportions in the United States, as well as in 

 Europe. Carrot juice is boiled down into a tasteless 

 jelly and when flavored with any fruit flavors passes 

 for genuine fruit jelly. 



It is further present in the unripe grains of corn, 

 at the base of the flowers of many grasses and in 

 clovers when in blossom. 



Pure cane sugar, free from water, consists of the 

 following elements, estimated in percentages: 



Carbon, 44.92; oxygen, 48.97; hydrogen, 6.11; 

 almost identical with starch. 



Second Grape sugar. This sugar is so called 

 from a peculiar species of sugar existing in the dried 

 grape or raisin, which lias the appearance of small, 

 round, or grape shaped grains. It gives sweetness to 

 "the gooseberry, currant, apple, pear, plum, apricot, and 

 most other fruits. It is also the sweet substance of 

 the chestnut, of the brewer's wort, and of all fermented 

 liquors, and it is the sugar of honey when the latter 

 thickens and granulates, or "sugars.'' 



It is less soluble in water than cane sugar, and less 

 sweet, two parts of cane sugar imparting as much 

 sweetness as five parts of grape sugar, at which ratio 

 forty pounds of cane sugar would equal 100 pounds 

 of grape sugar. Its chemical constituents are, in per- 

 centages : Carbon, 40.47 ; oxygen, 52.94 ; hydrogen, 

 6.59. Likewise nearly the same as starch. 



As a test to distinguish cane sugar from grape 

 sugar : Heat a solution of both and put in each a 

 little caustic potash. The cane sugar will be unchanged, 

 while the grape sugar will be blanckened and precipi- 

 tated to the bottom of the vessel. 



MANNA SUGAR, ETC. 



Manna sugar occurs less abundantly in the juices 

 of certain plants than cane or grape sugar. It exudes 

 from a species of ash tree which grows in Sicily, Italy, 

 Syria and Arabia. It is the product and main portion 

 of an edible lichen, or moss, very common in Asia 

 Minor. This curious lichen is found in small, round, 

 dark colored masses, from the size of a pea to that 

 of a hazel nut or filbert, and is speckled with small 



