STARCH OR PECULA. IW 



of the mealy part of the vegetable mixed with some other 

 substances: the product of this layer is known under the 

 name of common starch. 



The third layer contains the purest and heaviest starch ; 

 but in order to give it all the qualities it ought to possess, 

 it must be washed with water, and the water afterwards sep- 

 arated from it by filtration through a sieve of silk, so as to 

 free it from all impurities. With these precautions starch 

 may be obtained fitted for any use. 



As soon as the starch has been well washed, it is put into 

 baskets lined with linen, to be well drained. It is afl;erwards 

 divided into loaves, and the drying finished by exposing it 

 in the open air upon laths. Before packing for sale, the sur- 

 face of the loaves, which is slightly colored, is scraped, and 

 the drying of them is completed in the sun or in a stove. 



The use of starch and of fecula is very extensive ; starch 

 mixed with boiling water, takes the consistency of jelly, and 

 forms size ; when tinged with blue, it is used for giving a 

 gloss and stiffness to linen ; when reduced to a fine powder, 

 it is used for dressing the hair. Fecula forms the basis of 

 the greater part of our food, and is in itself an excellent 

 article of nourishment. 



Starch acted upon by sulphuric acid is converted into 

 sugar, and in this state may be made to undergo the vinous 

 fermentation. A few years since extensive establishments 

 were formed in France, for supplying numerous distilleries 

 with the fecula of the potato, which had been treated in 

 this manner. 



Starch thrown upon red-hot iron, burns, leaving scarcely 

 any residuum. 



Messrs. Gay-Lussac and Thenard have found that 100 

 parts of starch contain 



Carbon 43.55 



Oxygen 49.68 



Hydrogen 6.77 



So that in starch, as in gum and mucilage, oxygen and 

 hydrogen are combined in the same proportions as in water; 

 and those substances resemble starch in their characteristics, 

 and in their uses. 



