APPENDIX n. 



p. W. PIIILIPPI ON POTATO-STARCH AND GRAPE-SUGAR. 



Manufacture of Potato-starch. 



The manufacture of potato-starcli is so simple, and so many di- 

 rections have been given for it, that it will be unnecessary to en- 

 ter upon the matter fully. Only in regard to the wash or clean- 

 ing apparatus for the potato-mash I wish to engage the attention. 



The plain wash cylinders are in every respect excellent. They 

 are almost entirely constructed of wood and metallic wire net. 

 The cylinder consists of three separate pieces : the axle-tree, with 

 an arm made of wood, and the two halves of the cylinder form, 

 which are each separately covered on the inside with the required 

 number of metallic gauze. The cylinder is divided in 12 parts, 

 each division 4^ inches apart, consisting of wire gauze fastened to 

 fine wooden hoops in the cylinder. The axle rests upon a wood- 

 en;! frame in such a manner as to allow the potato-mash which en- 

 ters at one end to come out washed at the other. Under this cyl- 

 inder, resting on the same frame, is a box with tolerably high 

 sides, not to allow any of the washed substance to scatter. This 

 box has a fall of five inches. The rotation of the cylinder is from 

 12 to 16 times per minute. The water which is required to wash 

 the potato-mash is brought into a pipe lying horizontally and 

 above this cylinder. The under side of the pipe is sieve-like, to 

 allow the water free egress and fall upon the turning cylinder. 



This process may be repeated, and for that purpose a second 

 cylinder may be placed under the first, in such a manner as to re- 

 ceive the washed substance without any farther labor or direction. 

 It will be advantageous to have the wire gauze of the second cyl- 

 inder more fine than that of the first. Number 11 and 15 may 

 be used. 



Manufacture of Grape-sugar. 



1. The transformation of Starch-flour to Grape-sugar hy Acid. 

 — The first object is to procure the starch as clean as possible. 

 Should this be bought for this purpose, it is advisable to try the 

 following experiment : Take one pound of it, and dry it from four 

 to six hours upon clean paper at a heat of 80° E. After this 

 process it must be weighed, and the difference will show the quan- 

 tity of water contained in the starch ; or, take a few ounces of 

 starch in a small glass retqrt; add some diluted sulphuric acid, 

 and boil this from four to six hours. The sediment which re- 



