instead of the same quantity of salt, into the bread, as a seasoning. In the poorer parts of the country, they use equal parts of salt and alum.

Household bread.-There are but few bakers who make this bread; it is ordinarily made in those families who bake their own bread. As the brown farina retains a much greater quantity of water than flour does, so this bread remains fresh for a longer time than the white bread, but is apt to crumble. As it is not in general well kneaded, so it has a particular taste, which, although a little sour, yet it pleases many palates. It has likewise all the imperfections of being the first baking in an oven, which had become cold; and, therefore, they prefer to use sheet-iron ovens, and to substitute cast-iron or sheet-iron in place of the vault of bricks; and which iron ovens also serve to bake other alimentary articles. Holmes's oven is of this kind, and derives its heat from a mass of cast-iron which projects from its side into the fire-place, and thus no flues are required*.

They endeavour to increase the weight of bread in various modes; but, in general, at the expense of its nutritive qualities. Nevertheless they may employ gelatine to advantage, according to M. D'Arcet's process.

Sea biscuits. To make the best biscuits, or the American crackers, they take a good thin paste, and roll and double it many times, as if for puff-paste. The common seabiscuits differ from the preceding, in not being made with so many doublings. They make a thick paste, without leaven or salt, and in proportion as it extends beyond the feet, with which they knead it, they cut off the borders and throw them into the middle, and knead them anew. They thus obtain a biscuit, which breaks in plates. These are baked in a very low oven, which resembles a mufflé.

Spiced bread. (Gingerbread).—To make this, they dis

* The Editor possesses one of Holmes's ovens, and can testify to its great convenience and utility. He was rewarded by the Society of Arts, many years since, for this valuable invention.

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solve half an ounce of potash, and a little alum, in hot water; they then melt in it an ounce of butter, and knead it up with quick strokes, together with three quarters of a pound of treacle, and an ounce of mixed spices, of which the composition is variable; but for the most part consists of ginger, canella, nutmegs, and the four spices. Carawayseeds, aniseseeds, raisins of Corinth, almonds, and other confectionary articles, are also sometimes added. We may also omit the alum, and replace the potash, by the carbonate of magnesia, which, by the strength of a small quantity of it, enables us to compound it as follows: viz., Two pounds of flour, half an ounce of magnesia, one pound and a-half of treacle, two ounces of butter, and the necessary quantity of water to knead it, holding in solution a quarter of an ounce of tartaric acid, form a paste which will rise in half an hour. In France the spiced bread is made with honey, and rye meal, without any butter or water.

French bread.-The bakers in France commence their operations at five o'clock in the morning, by mixing five pints of water, and three pounds of leaven, reserved from the last baking, and as much flour as will make a paste, weighing seventeen pounds. Ten hours afterwards they add ten or eleven pints more water, and sufficient flour to make a paste of forty pounds weight; two hours afterwards, twenty-four pints more water, and flour enough to make a paste of the weight of one hundred and twenty pounds. From this paste they cut off a portion of three pounds in weight, to serve for the leaven of the next day's baking. Then, four hours afterwards, they make a new addition of one hundred pounds of flour, and from seventy to eighty pints of water, and which will yield a mass of about three hundred pounds weight. They then begin to beat the paste, and when it is well kneaded, they separate about eighty pounds of it, which is to serve as the leaven for the next baking. This paste is so fluid, that the loaves cannot preserve their form before they have been exposed to the heat of the oven. For the second baking, after hav

ing mixed the quantity of flour necessary, by kneading it, they add the paste reserved from the former baking, and, when the mass is finished, they cut off a part weighing eighty pounds, and thus they proceed a third time, a fourth, and so on, until they have made twelve bakings. They thus continue to work for several days together, only they modify it after every fourth baking, by adding what they term a young leaven to the paste which each baking had impaired or weakened. If they would introduce into the paste either salt or yeast; they thin it in a proper manner with water, which contains yeast or salt in solution. They also use yeast for the soft bread. A quarter of a pound of the yeast from beer is equal to eight pounds of the paste leaven; so that four ounces of yeast are equivalent to twenty pounds of the paste. The paste in which they have mixed the yeast, must not, however, be mixed with that containing leaven.

In France, they estimate the consumption of bread, including that used with soups, at two pounds and a quarter per person; whilst, in England, it is not quite thirteen

ounces.

French sea-biscuits.-To one hundred pounds of flour they add ten pounds of leaven, but older than that which is used for making bread, and with water, form it into a thin mass, which is well beaten. They finally cut it into bits, of a certain weight, flatten it with a rolling-pin, and prick it full of holes. It is baked for two hours.

German bread.-This is named semmel, and is made with fine flour and yeast; and they always make the paste a few hours before they bake it. The large semmels weigh about half a pound each; but the best not above two ounces; they are of an oblong form, and sometimes adhere in rows of five or six dozens. But, with the exception of these, all the bread prepared in Germany is made with rye meal and wheaten flour, of which the proportions vary. Their ovens are of an oval shape, and the vault is sufficiently elevated. In Russia their ovens are composed of plates of

cast-iron.

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372

LXXIX. On the manufacture of Red, Green, Yellow, and other Enamel Colours*.

Red. This is a primitive colour, that is to say, it is not formed by a mixture of other colours; it is generally obtained from iron. There are plenty of processes for making it; some consist in calcining the sulphate of iron, others in oxidizing native iron, by the aid of a strong heat and the contact of the atmospheric air. But the following is the manner of procuring the most beautiful red.

We must procure a quantity of steel, the best and finest which can possibly be had; the old blades of English razors are very good for this purpose. These must be broken into small pieces, and be introduced into a matrass containing sulphuric acid diluted with water. The solution may be made in the cold, but much better and quicker by the aid of heat. When it is effected, the solution must be poured into a porcelain bason, and be evaporated on a sand-bath, until the liquid has attained a certain degree of concentration; it must then be exposed to the open air, when crystals of sulphate of iron will be formed. When these have attained a proper size they must be taken out of the mother waters, and be placed upon a leaf of paper to be washed.

After the sulphate has been well purified, it must be dissolved in about three times its weight of distilled water, be filtered through paper, and evaporated a second time. It will then form, on cooling, crystals of the sulphate of a beautiful emerald green colour, and very transparent. After these have also been well washed and dried, they must be enclosed in a wide-mouthed bottle, with a ground stopple to it.

When we would prepare the red colour, we take one part by weight of the sulphate, and a quarter of a part of sulphate of alumine (alum), and grossly powder them, in order the better to mix the two salts; on the other hand,

From the Dictionnaire Technologique.

we make a charcoal fire in a calcining furnace, and when it is of a good glowing heat, we place a plate of thin sheetiron upon the coals, on which we have previously laid the two powdered sulphates. The aqueous fusion of the two salts takes place at the same time, but the mixture is at first white, and then reddens: we should therefore take great care not to make the fire too strong, lest we cause this red tint to fade. Finally, when we perceive that the colour is uniform throughout, we remove the plate from off the burning coals, and leave it to cool, and we may distinctly perceive that the more it approaches to the temperature of the atmosphere, the finer the red colour is developed.

Nevertheless, as we may always find in the calcined mass, certain parts of the oxide of iron where the red is of a more agreeable tint than in other parts, so we may select them. We deposit these selected pieces upon a glass slab, moisten them with distilled water, and grind them with a glass muller until we have reduced them to a very fine powder. When this is effected, we remove the colour with a pallete-knife, and place it in a porcelain vessel, when we wash it repeatedly with hot water, decanting the water each time; finally, we dry the residuum in a gentle heat.

In order to make known the reason for adding a fourth part of the sulphate of alumine to one part of the sulphate of iron, we must say that it is not because the colour becomes thereby finer and more intense; on the contrary, the alumine, by the white tint natural to it, tends to deaden the clear red which the iron manifests; but as that colour is extremely fugacious, the alumine by its refractory property, gives it a certain fixity which it would not otherwise possess; so that although this last substance predominates in the composition, yet the red colour is more fixed, although less intense. But we must not proceed beyond the due limits in this respect.

This red is greatly employed in vitrefiable painting;