:298 Dr. Ives on Potatoes. 



analysis of Einhoff, 7680 parts of potatoes afforded 11 o3 parts 

 of starch — fibrous matter analogous to starch 540 parts — albu- 

 men 107 parts — mucilage 312 parts. The sum of these pro- 

 ducts amounts to about one-third of the potatoes subject to the 

 experiment. 



Sir Humphry Davy observes, that one-fourth of the weight 

 of potatoes at least may be considered nutritious matter. 



One-fourth of 22400, the product of an acre of ground, cul- 

 tivated with potatoes, is 5600. The whole weight of a crop 

 of wheat calculated at 30 bushels to the acre, and at 60 pounds 

 to the bushel, gives 1800. Deducting one-sixth from the wheat 

 as matter not nutritious, and the weight is reduced to 1500. 



The nutritious matter of the crop of potatoes to that of 

 wheat is as 6600 to 1500, or as 56 to 15. 



The starch might be obtained by a very simple machine, 

 i^commended by Parmentier ; and in seasons when potatoes 

 are abundant, the potatoes might be converted to starch, and 

 the starch preserved for any length of time, and used as a 

 substitute for wheaten flour. 



The machine alluded to is a cylinder of wood about three 

 feet long and six inches in diameter, covered with sheet tin, 

 punched outward so as to form a coarse grater, and turned by 

 a ci-ank. This cylinder is placed in a box of boards whose 

 sides slope a little inward upon the principle of a hopper, and 

 a tub of water is placed beneath: The potatoes are thrown 

 into this box, and as the crank is turned they are crushed, and 

 the starch or fecula subsides to the bottom of the water. It 

 is well known, that potatoes are largely used in England 

 mixed with flour to form a very good bread ; the starch of the 

 potato would of course answer much better. 



