338 



STARCH. 



niar overhauling," and send the report of the discus- 

 sion for publication. You will thus be able to keep 

 the editor and his correspondents pretty nearly right. 



tides broken by pressure and water (the internal 

 matter remaining solid), c,/, g. 

 • Fig. 2 represents the grains of the West Indiaa 

 arrow-root. 



STARCH. 



A coRRESPOHDENT who has on hand a large crop 

 of potatoes, and is somewhat troubled with what we 

 think an entirely unnecessary fear, that potatoes this 

 winter will be " sold for a song," writes to know if 

 they can profitably be made into starch. Potatoes 

 contain say about 15 per cent, of starch, and corn 

 80 percent; so that com at .^1.25 per bushel is 

 cheaper for the purpose of making starch, than pota- 

 toes at 25 cents. Potato starch is not valuable for 

 the manufacturer, as it absorbs water more readily 

 than other starch. While on this subject, a few facts 

 and illustrations will not be uninteresting to our 

 readers. 



Starch is an abundant vegetable product. It is 

 deposited in the grains, seeds, roots, stems, and fruits 

 of many plants. Potatoes (different varieties) con- 

 tain from 10 to 20 per cent, of starch; buckwheat, 

 52 per cent; barley meal, 67; oat meal, 59; rye 

 flour, 61; wheat flour, 56 to 72; Indian corn, 80; 

 rice, 82 ; peas, 32 ; and beans, 35 per cent 



Pure starch is a snow-white powder of a glistening 

 aspect, which makes a crackling noise when pressed 

 with the finger. It is composed of transparent 

 rounded grains, the size of which varies in different 

 plants from one three-hundredth to one three-thou- 

 sandth of an inch in diameter; being largest in the 

 potato, and smallest in wheat. Examined by a 

 microscope, the whole surface of the grain appears 

 covered by parallel rings, which seem depressed or 

 cut into it The grains have a laminated texture, 

 consisting of a series of concentric layers or mem- 

 branes, the outermost of which is the thickest or 

 firmest. 





) 



The 



2. — AKKOW ROOT STARCH. 3. — SAGO STARCH. 



In fig. 3 are seen grains of the sago meal. Sago 

 is the medulla or pith of the stems of various species 

 of palm; it is manufactured principally in the Moluc- 

 cas, and comes to us in the forms of sago meal, pearl 

 sago, and common sago. The first is principally 

 employed in making sago sugar; the second is gen- 

 erally used for domestic purposes. Common or 

 brown sago comes to us in brownish-white grains, 

 varying in size from the grains of pearl barley to 

 those of peas. 



Fig. 4 shows the entire grains of tapioca. 

 Brazilian plant from the ^s^ 



roots of which the tapioca 

 is obtained, is said to be 

 poisonous. The irregular 

 lumpy form in which the 

 article is found in our mar- 

 ket, is owing to its being 

 dried on hot plates. 



Fig. 5 exhibits a section of the stem of the sago 

 tree, showing the pith from which the sago is ex- 

 tracted. The tree grows to the height of thirty feet 

 or more, and measures five or six feet in circumfer- 

 ence. One large tree will yield from two to four 

 hundred pounds of sago flour. 



Fig. 4 ENTIRE GRAINS 



OP TAPIOCA. 



Pig. 1. — GRAINS OP POTATO STARCH. 



Fig. 1, representing the grains of potato starch, 

 shows the normal starch particle, a; irregular starch 

 particle, 6; particles each having two hila, c, d; par- 



Pio-. 5. — STEM OP THE SAGO TREE. 



Starch is obtained from potatoes by grating them, 

 and washing the pulp upon a sieve. The water car- 



