1 174]

The liquor which has paſſed through the ſieve is of a duſky colour, and muddy: in proportion tothe extraive ſubſtance which it contains diſ- folvable, it depoſits in the courſe of five or ſix hours all the flour which it kept back. When the depoſit is formed, the water is racked off as uſeleſs; a conſidlerable quantity of freſh water is then poured on the flour remaining. The flour is left to ſteep, in order to cleanſe it; and it is left in this ſtate till the next day. A fimilar depoſit of flour is obſerved; the water is racked off as uſeleſs. The flour is again diluted with a freſh ſupply of water, and the mixture is paſſed through a ſilken ſieve, rather of a cloſe texture. The fmall quantity of parenchyma which had paſſed with the flour through the horſe-hair ſive now remains on the filken ſieve. The water is left in a ſtate of reſt till the flour is well reunited: if the water floating above it appears perfectly clear, without the leaſt colour or flavour, then the proceſs is completed; but while the leaſt flavour or tinge remains in the water, another waſhing muſt be performed, until the fmalleſt particle of the ex- tractive fubſtance is obtained.

When the flour is ſufficiently laved or waſhed, it is taken from the tub with a wooden ladle, and placed upon hurdles of reeds, covered previouſly with paper, that the flour may dry and be ſcreened from duſt: when it is ſufficiently dry, it is paffed through a filken ſieve to clear it of any impu- rity remaining; after which, it is laid by in glaſs veſſels, merely covered with paper.—.

REMARKS.

The major part of the potatoe-flour prepared for ſale contains ſome par- ticles of ſand, perceived when between the teeth: this proceeds from care- leſſneſs in the waſhings. It is not an eafy matter to clear away the ſand lying in the knots and folds of the root. The mode of cleaning theſe roots, though apparently fimple, requires nevertheleſs much care and at- tention: the ſame may be ſaid of preſerving the whitenets of the flour. The /ecula is perfectly white; if it is wiſhed to obtain it ſo, it muſt be ſepa- rated with care by fufficient waſhings from all extractive matter. This muſt be done in ſweet and clean veſſels, that will not communicate any diſ- agreeable flavour: earthen-ware would be the beſt; but that is imprac- ticable on a large ſcale: wooden tubs become unavoidable: deal is prefer- able to oak; which latter is apt to communicate ſome tinge, if the ex- tractive matter has not been exhauſted by being long and often in water.

The mill, being fixed in a tub of water, never becomes choaked; but

as the raſped potatoes ſoon form a maſs at bottom, it is proper to remove them from time to time, to prevent them from being choaked. The pulp

—

——³——