STARCH. 



75 



while dryings it splits into those curious long angular frag- 

 ments in which we usually see it. Latterly the Germans 

 have sent us some very fine samples of wheaten starch in 

 thin round sticks^ about three inches in length and the six- 

 teenth of an inch in diameter; we however import very 

 little wheaten starch, owing to the high duty^ — not more 

 than two to three tons are imported annually. 



Potato starchy made from the common potato^ Solanum 

 tuberosum [Solanacece] , by an exactly similar process to that 

 detailed above^ is an article of considerable importance as 

 an import^ and also as a cheap substitute for wheaten starch ; 

 it is always in the form of a fine glistening powder^ and is 

 usually imported from France and Holland, in sacks and 

 bags. It is very extensively used in the manufacturing 

 districts for dressing calicoes, muslins, etc. When heated to 

 210° starch becomes altered from a substance insoluble in 

 cold water to one perfectly soluble both in cold and hot 

 water; this is in appearance the same as the starch, but 

 when dissolved has all the properties of gum, and is now 

 extensively used under the name of British gum, which is 

 employed for various purposes, especially rendering postage- 

 stamps and envelopes adhesive. Potato starch so altered is 

 called Dextrine. It also is imported in sacks from Prance ; 



