338 THE POTATO AND ITS COMMERCIAL PRODUCTS. 



upon a large or small, cheap or expensive scale. No grower of potatoes 

 to any considerable extent ought to be without this addition to his agri- 

 cultural implements or machinery, especially in those parts of the country 

 where it is difficult to dispose of a crop of unsound potatoes, and it may not 

 be convenient to consume them by cattle or pigs. In such cases, the 

 diseased tubers are scarcely worth the raising. The money produce of 

 manufacturing the potatoes may be stated as follows : 



One ton of potatoes, or 2,2401b., produces, at 17 per cent., £ s. d. 

 3 cwt. 1 qr. 161b. of starch, at 22/. per ton - - - 3 35 



One cwt. of residue 110 



£4 6 



Against this must be charged the expense of manufacture, and the wear 

 and tear of machinery, neither of which is at all costly, as they do not 

 require skilled labour or complicated machines. 



Were it not for the excise, the starch, when extracted, might easily be 

 converted into sugar by a chemical process, every cwt. of starch (1121b.) 

 producing 1401b. of sugar. This process, however, is both complicated and 

 expensive, and would only be remunerative upon a large scale, which is 

 not the case with the manufacture of starch, which may be performed by 

 women in even a less expensive mode (on a small scale) than the one I have 

 described. 



Tbe proportion of starch contained in the tubers varies from 12 to 23 

 or 24 per cent. ; and the average may be about 16 or 17 per cent. At the 

 latter rate, a ton will produce 3801b. of starch. The price also varies 

 according to the proportion between demand and supply. It is sometimes 

 as high as 30/. per ton ; and in 1847, when so much was manufactured 

 from the diseased potatoes, especially in Ireland, the price fell as low as 12/. : 

 but it is seldom lower than 20/., and probably from 22/. to 24/. may be 

 reckoned as the average. It is extensively used by the cotton manufac- 

 turers in the North of England and Scotland ; and a great deal of it is sold 

 by the grocers as arrowroot, to which it has a great resemblance. 



The residue, of which about 5 per cent, remains, after being pressed and 

 dried will keep any length of time ; but, if suffered to lie in a damp 

 state, it very soon becomes putrid and worthless. If proj)erly economised, 

 it is a valuable food for cattle and pigs. When dried, the pidp is worth 

 from 10/. to 12/. per ton. The water, in which the pulp is washed contains 

 the soluble constituents of the potato, and is used in France as liquid 

 manure with considerable advantage, especially in the neighbourhood of 

 Paris, where large quantities of starch are made. 



Thus every particle of the healthy or even diseased potato, if properly 

 economised, may be turned to the profit of the grower. 



Mr John Towers states that — 



1st. From 81b. of wnpeeled potatoes he obtained — lb. oz. 



Amylum, or starch ------ 1 6 



Pulp, pressed by the hand - - - - 111 



The loss in watery or soluble matter - - 4 15 



