44 IKK SWKE'l' iMjTATO. 



Yield Starch 



I'er Acre. Starch. I'er Acre. 



Pounds. I'er cent. Pounds. 



Wheat ] .200 57 684 



Corn 1,900 65.5 1.283.8 



Sweet Potatoes 12,000 22.0 2.040.00 



This is based on a yield of 200 bushels per acre 

 and 22 per cent, of starch. Two hundred bushels 

 are even now. with talkie varieties, considered a mod- 

 erate yield. With a yield of 500-600 bushels with the 

 varieties which are reported from the South, and 

 28-29 per cent, of starch from selected varieties, the 

 yield of starch per acre would be simply enormous. 

 The Irish potato, which is raised for starch exten- 

 sively in Germany and France, yields only about 

 14-21 per cent, of starch, and 150-300 bushels of 

 tubers per acre. 



We see, then, that it is well established that the 

 sweet potato contains enough starch to be considered 

 as an excellent source for its manufacture. We now 

 have to consider the other sides of the question: 

 What is the quality of the starch? and, Can it be 

 profitably extracted,? 



Wiesner ("Rohstotfe") states that the sweet 

 potato starch commonly manufactured in Martin- 

 ique, Guadeloupe, Eeunion, Cochin China, India, etc., 

 which has been exhibited at various world's fairs, 

 is not pure white, but grayish-yellow. By washing 

 this in pure water he obtained a much whiter prod- 

 uct, but not pure white. He thinks, however, that 

 a process might be found by which a jDure white 

 product could be obtained at once. He cites Gintl 

 (Appreturmittel, p. 4) for the statement that sweet 

 potato starch is even now imported to England in 

 limited quantities from the tropics, to be used for 

 technical purposes. 



