4 0

1 2 4 0 3 Excellent bread; superior in colour to No. 4, and rather more compact; this quantity of wheaten flour alone, as appears by No. 7, would have produced 2 lb. 10 oz. of bread; consequently the actual proportion of the produce of the potatoe in this loaf is 1 lb. 6 oz. or, as nearly as possible, one-third.

51 0.10 2 10 4 Rather dark; the appearance of

7. 2 0 Flour.

8. 2 0 Flour. 08 Farina

54 0 101

0 1

this loaf indicated that the yeast used for this batch was not good.

10 3 433 Excellent bread; whiter than bread made of wheaten fleur alone; no flavour whatever of potatoe; not used until nine days old.

50 101

3 0 1

8 Rasped Potatoes 0 0 01

From these experiments it appears that various proportions of potatoes and farina are highly palatable in bread; but if it be calcu

lated that not more than one-fifth part be generally introduced into consumption, the operation of that fifth is sufficiently great to produce all the effects in view, in recommending its general adoption.

Some kinds of potatoes contain a much greater proportion of arina than others, some yielding a seventh part, and even a still larger proportion of it. Experience will best determine the most desirable sort for use, as other kinds produce more abundantly in number; all these considerations should be attended to.

Potatoes may be manufactured into farina during the greater part of the year, but they lose a portion of their farinaceous matter when vegetation begins; the manufacturer, therefore, should provide an early sort to commence his operations upon in August, and cease to grind any after the months of April and May.

Frost-bitten potatoes yield nearly as good farina as the others, provided they are ground before they begin to decay; and potatoes kept over for a whole season, although of inferior value, may by this process be still rendered serviceable food for mankind. These are advantages which ought not to escape notice. Frost-bitten potatoes have hitherto become in a short time a total loss, and farmers have generally been afraid of extending their cultivation of potatoes, for fear of their being spoiled by keeping, both which inconveniences are avoided by preparing the farina from them.

Amongst the many important uses to which the farina may be applied, that of biscuit for sea store is of great consequence. Biscuits made from one part farina and two parts of wheaten flour are whiter and better than those made wholly of common flour. Baked biscuits of these proportions have been repeatedly made with uniform success; and as the farina is in itself less corruptible than wheaten flour, it is likely to produce a biscuit of a less perishable kind. Some have been already kept nearly twelve months without exhibiting any symptoms of moisture or decay; on the contrary, they were as hard and as good as on the day they were baked. Biscuit differs from leavened bread in this circumstance, that all moisture is evaporated from biscuits in baking, whilst it constitutes an essential quality in bread; the weight of bread is greater, the weight of biscuit is less, than the flour of which it is composed. It is, therefore, not inconsistent with the nature of farina that it should exhibit more moisture in bread, and yet discover no symptom of it in biscuit; and it has one convenient property, of which a baker who manufactures it may avail himself, that it may be used for bread or biscuit either in a wet or dry state; consequently the expense of drying it may in some cases be avoided. Its introduction into biscuit would produce a saving of one-third of the wheaten flour now used for that purpose, which will be found very great, when the extensive use of biscuit in the navy and army is considered. The farina of potatoes should constitute, from its general application. a part of the stores of each.

In the navy particularly, the farina would afford a great variety of food, as it forms an excellent ingredient in soup as a substitute for

peas, oatmeal, and rice, and possesses the superior advantage over
those substances of not being susceptible of injury. One ounce of
farina will thicken sufficiently nearly one quart of water. And
when this soup is flavoured with onions, celery, leeks, &c. and
seasoned with pepper and salt, it forms a very palatable mixture
The produce of 21 lbs. of raw potatoes
without the aid of meat.
made into farina, and soup formed from it, will furnish a whole-
some meal to 28 persons, allowing each person a full quart, which
potatoes, in their original state, would scarcely furnish a dinner to
one-third of that number.

The farina of potatoes will form a thick mucilage with 26 times its weight of water.

In all cases where the farina is intended to be converted into a gelatinous state, the farina should be previously mixed with some portion of the liquid cold.

A dessert spoonful of the farina mixed with a little cold milk and salt, and added to a pint of boiling milk, and kept stirring and simmering, will form an excellent nutriment.

From various circumstances, it appears that the article called Semolina in the shops, and recommended as a nutritious diet for children and sick persons, is wholly composed of the farina of potatoes.

Certificates.

Mr. Whately, of Cork, has shown me a specimen of flour made from potatoes; and also of biscuit, made partly from this flour, and partly from the flour of wheat. I am convinced that this flour is very wholesome and very nourishing, and may be of great use to the public in supplying the deficiency of wheaten flour.

Lower Grosvenor-street,

Dec. 11, 1812.

M. BAILLIE, M. D.

I have examined the flour from potatoes made by Mr. John Whately, and have no doubt of its containing all the nutritious part of the potatoe, and therefore calculated to form a very good and valuable diet; and as the flour thus produced may be readily transported to any distance, and may be kept for a very long time without losing any of its nutritive properties, I think the conversion of potatoes into flour may prove highly advantageous to the community.

Soho-square, Jan. 17, 1813.

GEO. L. TUTHILL.

Reference to the Engravings.

This machine is of a very simple construction, its moving part consisting of a cylinder covered with tin plates, pierced with holes, so as to leave a rough surface, in the same manner as the graters used for nutmegs, &c. but the holes in this are larger. This cylinder is situated beneath a hopper, into which the potatoes are

thrown, and thence admitted into a kind of trough, where they are forced against the cylinder, which as it revolves grinds the potatoes to a pulp.

Fig. 1, Plate XXXIV., represents the machine in front, or lengthways of the cylinder; and fig. 2 is a section through the middle of it, showing also the hopper with its contents, and the manner of the action of the machine. A represents the handle, by which motion is given to the machine: it is fixed upon the end of the axis of the grating cylinder B; on the opposite extremity of this axis is a fly-wheel C, to regulate and equalize the movement. D is the hopper, into which the potatoes are put; and pressing by their weight upon the top of the cylinder as it revolves, they are in part grated away. On one side of the lower part of the hopper is an opening, closed or opened more or less at pleasure by a slider E; and the degree of opening which this has regulates the passage of the potatoes from the hopper D into the trough F: this is as wide as the length of the cylinder, and has a concave board G fitted into it, which slides backwards and forwards, by the action of levers a a affixed to an axis H, extended across the frame of the machine. K is a lever fixed upon the middle of this axis, and terminating in a hook at the end for the suspension of a weight L; this acts upon the board G by means of the levers K and a a and the rods b, to force or press the potatoes contained in the trough forwards against the cylinder, and complete the grating of them into a pulp.

A line c is tied to the end of the lever K, and passing over a pulley d, hangs down within reach of the person who turns the handle of the machine. By drawing this line, the weight at the end of the lever K is raised up, and by the rods & the board G is withdrawn to the extremity of the trough, and a fresh stock of potatoes falls out at the opening E from the hopper into the trough; then, the line being let go, the weight L presses the board against the potatoes, and forces them against the cylinder, which by its motion grates them away very rapidly, the pulp passing down the space between the edge of the lower board of the trough F, and the cylinder, which space is only a narrow crevice that nothing may pass down but the reduced pulp, which falls into a box or vessel situated between the frame at M. The board G is perforated with a number of large circular holes, to make an uneven surface, in which the potatoes remain steady, whilst exposed to the action of the cylinder upon their opposite sides.

The tin plate covering the cylinder is of course pierced from the inside outwards, and the bur or rough edge left round each forms an excellent rasping surface, for the reduction of such substances as the present. The frame of the machine requires but little explacation, merely consisting of a square frame, containing the cylinder, and supporting the hopper. This frame stands on four legs, two of which rise up to a sufficient height to carry the pivot of the axis H. The legs are morticed into four ground cells, which may be made

to receive a box or chest, fitted in the manner of a drawer, to contain the pulp as it falls from the machine, or it may fall into any vessel placed underneath.

The pulp in the vessels in which it is collected should be completely immersed in water, and well stirred; the separation of the farina, by its falling to the bottom, will speedily take place. The fibrous and refuse parts should be first removed, and the farina afterwards repeatedly washed, until it no longer communicates any tinge to the water. It is then sent to the stove or drying apartment, put into boxes, and dried. Care should, however, be taken that it does not dry too rapidly. Wherever the business is conducted upon a large scale, a machine for washing the potatoes should be erected, and it might be contrived to receive motion from the power that directs the grinding machine. The vessels containing the pulp should be so arranged that a stream of water could be made to pass through them at pleasure. The pulp, after the first separation of the farina, still retains a quantity of farinaceous matter; but it will, perhaps, be more profitable to convert it into food for hogs, with such other additions as may be thought necessary, than to steep it again for the purpose of extracting any remaining portion of farina. It will be probably best to give it to the hogs boiled, along with a moderate proportion of boiled potatoes. This disposal of the refuse pulp would nearly defray the whole expense attendant upon the manufacture of the farina.

**This machine would operate with good effect for reducing apples to a pulp for making cider, as it is extremely expeditious and effectual in its operation.

Models of two machines proper for washing the earth from potatoes may be

seen in the Society's repository.