at the same rate the biscuit web travels, so that they are ready for being immediately placed on the travelling stage of the patent oven. The processes are so arranged that the oven carries forward the biscuits as quickly as they are delivered by the cutting machine, and in some cases the ovens are fed direct from the cutting and panning apparatus by automatic machinery. The patent travelling ovens are constructed from 30 to 44 feet long, and fitted with endless webs either of plates or chains. The chain webs are used for baking small and fancy biscuits, such as are placed in trays, and the plates are used for large and plain water biscuits, which are placed by hand on the travelling plates. The rates at which biscuits of different sizes and degrees of richness must traverse the whole length of the oven varies from about five to forty minutes, and the temperature of the oven has also to be modified to suit the various qualities. Both the heat and rate of motion are under easy and adequate control in the patent ovens.

There is an endless variety in the form and composition of plain and fancy biscuits. In the trade list of Messrs. Vicars, of Liverpool, the chief manufacturers of biscuit machinery, the names of 128 varieties of cutters are mentioned. In the making of fancy biscuits, milk, eggs, sugar, butter or lard, and flavoring essences are extensively used, and in these cases the proportions of the various ingredients are roughly mingled before being sent down the shoot into the mixer. The richest class of biscuits, the dough for which is necessarily soft, are cut out by hand labor, and fired on trays in common ovens. The dough for rout biscuits is placed in a strong metal box or chamber in which a piston is tightly fitted. The piston is moved forward by a screw, and it pushes the dough through a series of holes or dies. The dough is received on a sliding board, and is cut into proper lengths by a knife. Cracknels are made without either milk or water being used to mix the dough, eggs alone being employed for this purpose. Certain proportions of butter, sugar, and sesquicarbonate of ammonia are added to the mixture of flour and eggs, and the dough is baked in the usual way. The cracknels, when cut out, are thrown into a boiler of boiling water, and in about two minutes they float to the top. They are then fished out and thrown into cold water, and then drained on cloths, panned, and fired in an ordinary oven at a high heat. In the firing, the ammoniac carbonate, being very volatile, is driven off, and the cracknel thus assumes its spongy structure. Many other varieties of biscuits are rendered light and spongiform by the use of the sesquicarbonate of ammonia, or of carbonate of soda, in conjunction with sour milk. In the firing of biscuits, not only the moisture of the dough is driven off, but a certain proportion of the water held by the flour in its apparently dry state, so that from 10 lb of flour only about 9 tb of water biscuits are obtained. The composition of plain biscuit is given by Dr. Parkes as follows:Water.................. 8 to 12 Nitrogenous substances.. 15 Dextrin

3.8

:

1.9

Sugar.................
Fat...................................
1.3
Starch................72 to 75

Loaf-bread. VESICULATED BREAD.-Under this head is included such bread as is rendered spongiform in structure by the action of carbonic acid within the dough, and which is not baked hard and dry as in the case of biscuits. It includes ordinary loaf bread, pan loaves, French or Paris loaves, cottage loaves, bricks, rolls, buns, and many varieties of fancy bread distinguished by local names and minor differences of form and composition. Vesiculated bread is made in three different ways:

1st, By the development of carbonic acid within the dough through fermentation of the flour. This is the ordinary and principal method of bread-making.

2d, By mixing the dough with water previously aërated with carbonic acid. The aërated bread made under the patent of the late Dr. Dauglish is thus manufactured.

3d, By the disengagement of carbonic acid from chemical agents introduced into the dough. Dodson's patent unfermented bread comes under this head, and the "baking powders" and "yeast powders" extensively sold consist generally of carbonate of soda or ammonia and citric or tartaric acid, which evolve carbonic acid in presence of

water.

Fermented Bread.-The manufacture of fermented or leavened bread is, as has already been hinted, of very great antiquity, and it is still by the fermentation process

that breads chiefly made. In ancient times leaven was employed to induce fermentation in dough ("a little leaven leaveneth the whole lump," Gal. v. 9), and to this day Parisian bakers, who excel all others in the quality of the bread they produce, chiefly use the same ferment. Leaven is simply a portion of dough, put aside from a previous baking, in which the fermentative action has reached an advanced stage of activity. Yeast, however, has been used as a ferment from an early period, and it appears that it was first so employed in France. Pliny says (Nat. Hist., xviii. 12), Galliæ et Hispaniæ frumento in potum resoluto, spuma ita concreta pro fermento utuntur; qua de causa levior illis quam cæteris panis est." The use of yeast appears to have died out in France, but was revived again towards the end of the 17th century, when its reintroduction was violently opposed by the Faculty of medicine of Paris. Yeast is now used by Parisian bakers for fancy bread and pastry only.

The baking of fermented bread involves three distinct operations, which are technically denominated "setting the sponge," making the dough or kneading, and baking or firing. It will be convenient first to describe these processes as they are conducted in a London bakehouse. The first duty of the baker is to mix a ferment, which consists of a mixture of potatoes, yeast, and flour. The potatoes, in the proportion of 6 lb to a sack of flour, are boiled and mashed in a tub, and water is stirred in till the mixture is reduced to a temperature of from 70° to 90° Fahr. About 24 pints of yeast and 12 tb of flour scalded in boiling water are then added, and the whole forming a thin uniform paste is set aside for several hours, during which it undergoes an active fermentation. Setting the sponge consists in mixing the ferment in a large trough with flour and water sufficient to make the whole into a rather stiff paste. The flour used at this stage, when "full sponge" is made, should be about one-half the entire quantity intended to be used in the "batch," and the ingredients have to be thoroughly incorporated by the workman stirring them laboriously together with his arms. The operation occupies from twenty minutes to half an hour, and when ready the sponge is covered over and allowed to rest for several hours according to the temperature at which it is maintained. Generally in from four to five hours the sponge "rises;" fermentation has been going on, and carbonic acid steadily accumulating within the tenacious mass till it has assumed a puffed out appearance. By degrees the sponge gives off the gas in puffs, and the mass begins to collapse, till what was a swollen convex surface assumes a somewhat concave form, the centre being depressed while the sides adhere to the edges of the trough. The workman judges by the amount of collapse the time the sponge is ready to be taken in hand for kneading or making the dough. This process is thus described by an eye-witness:— "The batch consisted of a sack and a half of flour, nearly one-half of which had been used in making the sponge. Two men commenced breaking the sponge at 1.4 P.M. Having poured the water into it, they plunged their arms in and stirred it about until it became of the consistency of thin batter. At 1.10 they began to mix the dry flour with it, immediately upon doing which they were enveloped in a cloud of flour dust, their heads being bent down to with in a few inches of the mass they were handling. Flour and pieces of dough were splashed over the trough upon the floor. At 1.12 a third man was added. Their hair caps, and face powdered thickly with the dust, a thick cloud of which was thrown up with every movement, espe cially when large masses of dough, as it became a little solid, were taken up in their arms and thrown upon the rest, fresh flour being first strewn between. At 1.15 one of the men became very red and heated. The other two were very pale, and did not show any perspiration. At 1.16 the cutting off of large masses began, as much as two men could lift to place over the adjoining mass. At 1.23 the men began to pound the mass with their fists. At 1.26 one of the pale men, who was also very thin, began to look red and hot. At 1.29, after smoothing the mass down, they began again to pound it with their fists. At 1.30 it was again smoothed over, the sides of the trough scraped, and a little dry flour thrown over it. It was then considered finished." After this laborious process the finished dough is covered over for some time, varying from half an hour to two hours according to the temperature, during which 1 Tremenheere's Report on Journeymen Bakers.

fermentation again begins, and the mass is "proofed." It is then "scaled off," i.e., weighed on scales in pieces of 4 b 4 oz., if 4-lb loaves are to be made, or half that amount for 2-lb loaves; and as rapidly as weighed it is "moulded' into the form of the loaf, when it is ready to put into the oven. Flour of good quality will take up about 17 gallons of water in course of the foregoing operations, and before putting into the oven the ingredients of a 4-tb loaf

will be

A loaf ready for going into the oven has about half the bulk it attains during the process of firing. Batches of cottage and household loaves are packed close side by side on the sole of the oven, the sides of each loaf being rubbed with butter to prevent them from adhering to each other, and they are consequently crusted on the top and bottom only. Pan loaves are baked each in separate tinned pans of the form of the loaf, and Parisian loaves are baked end to end in long tinned pans. The firing of bread in the oven occupies from 1 to 14 hours, the temperature at the beginning of the process being from 550° to 600° Fahr. The baker can ascertain if the oven is at a proper temperature by throwing a little flour on the sole of the oven, which ought to turn to a light brown color. Ovens in London are usually built of brick, with a sole only 24 inches thick; in Scotland stone is used, the sole being from 10 to 12 inches thick, and the oven consequently retains heat much more effectually.

In Scotland the system of using ferments is not generally practised as in London, some of the varieties of yeast or barm being mixed directly with the flour. In some localities the system of setting "quarter sponge" is adopted, in which the sponge originally prepared contains only onefourth of the flour to be used. To this, after an interval of about twelve hours, more flour and water are added, which brings it up to half sponge, and about two hours thereafter the mass is ready for making the dough. In Paris, where bread-making is carried to the highest perfection, leaven, as has already been mentioned, is the fermenting agent employed. This consists of a portion of dough laid aside from a previous baking in a uniform temperature for seven or eight hours, during which it swells and acquires an alcoholic odor. This, termed "the chief leaven," is taken and worked up with flour and water to a firm paste double its original mass, when it becomes "the first leaven." After an interval of six hours the amount is again doubled, forming the second leaven. The "complete leaven" is formed by doubling the size of the second leaven, and the proportion the complete leaven bears to the finished dough is about one-third in summer and one-half in winter.

Sound flour yields from 90 to 94 4-lb loaves per bag of 280 lb, some "strong" " flours giving even a greater quantity of bread. A table of experiments, conducted by Messrs. Lawes and Gilbert, gives a mean result of 135-2 of bread from 100 of flour; and in the observations of a large number of English and French authorities quoted by them, the ratio of bread to 100 of flour varied from 127 to 150. The following table gives the mean of 25 analyses of the bread of London bakers by Dr. Odling :

Organic matter................
Mineral matter or ash

Percentage of ash in dry bread.

43.43

.55.26

1.30 .........2:30 nitrogen in new bread............1.26 66 in dry bread... ........2-22

The bakers' standard of excellence of flour, apart from the question of color, is the weight of bread it will produce of a proper dryness and texture. The "strength" of flour in this respect appears to depend much more on its condition than on the absolute percentage of its constituents.

Panary Fermentation.-It would be altogether out of place in this paper to refer to the conflicting theories as to the cause of fermentation in organic substances. The socalled panary fermentation in bread-making is a true alcoholic fermentation, and whether induced by yeast or leaven the result is precisely the same. The gluten of the flour is the fermenting agent, and it is stirred into activity by

contact with a glutinous body already in an active condition, which may be either yeast or leaven. In this condition it exerts a fermentative influence over the sugar which may either have existed previously in flour, or which is at least immediately developed in it by the influence of moisture. The active gluten splits up each molecule of sugar into two of alcohol, two of carbonic acid, and one of water, and consequently an infinite number of minute air bubbles are developed throughout the fermenting mass. The reaction is shown in the following equation: CHO,=2C,H,O+2CO,+H,O.

'As the evolution of carbonic acid and alcohol proceeds, the sponge gradually swells, the little bubbles coalesce and enlarge, rising through the tenacious mass till the surface is reached, and then the carbonic acid bursts out and the dough begins to fall. This process would go on a considerable time, but the alcoholic fermentation would soon pass into an acetous fermentation and the sponge would become sour. When acetous fermentation ensues, as not unfrequently happens in baking, it may be remedied to some extent by the addition of bicarbonate of soda to the sponge. The late master of the mint, Dr. Thomas Graham, was the first to demonstrate the presence of alcohol in fermented dough, and he thus described his experiment:-"To avoid the use of yeast, which might introduce alcohol, a small quantity of flour was kneaded, and allowed to ferment in the usual way to serve as leaven. By means of the leaven the fermentation had arrived at the proper point, formed a considerable quantity of flour was fermented, and when into a loaf. The loaf was carefully enclosed in a distillatory apparatus, and subjected for a considerable time to the baking temperature. Upon examining the distilled liquid, the taste and smell of alcohol were quite perceptible, and by repeatedly rectifying it, a small quantity of alcohol was obtained, of strength sufficient to burn and to ignite gunpowder by its combustion. The experiment was frequently repeated, and in different bakings the amount of the spirit obtained of the above strength was found to vary from 0.3 to 1 per cent. of the flour employed." Although the temperature of the oven drives off that amount of the spirit, fermented bread is yet found to retain a proportion of alcohol, as much as from 0-221 to 0-401 per cent. having been found in different specimens of baked bread. Speaking in 1858, Dr. Odling estimated the amount of alcohol thrown out into the atmosphere from the bread baked in London as equal to 300,000 gallons of spirits annually. Many years ago a patent was secured by a Mr. Hicks for collecting and condensing the alcoholic fumes from bakers' ovens, After an expenditure of £20,000 the attempt had to be and a company was formed for working the invention. abandoned, not from any failure to obtain the spirit, but because the bread baked in the process was dry, unpalat

able, and unsalable.

When what is termed "whole wheaten flour"—that is, the entire substance of the grain, excepting only the outer bran-is baked, it is known that the resulting loaf is of a dark brown color, sweetish in taste, and liable to be somewhat heavy and sodden. The brown color was at one time supposed to be due to the presence of brán particles in the flour, and in 1846 an American, Mr. Bentz, invented a process for removing the outer cuticle of wheat before grinding, it being supposed that the flour so prepared would yield a loaf of white color, while utilizing a larger proportion of the substance of the grain than is commonly used. To the astonishment of experimenters, however, the bread made from such flour was found to have the color and other characteristics of whole wheaten bread. The subject was investigated by an eminent French chemist, M. Mège Mouriès, who found that the peculiar action of whole wheaten flour was due to the presence in the outer part of the seed of a peculiar nitrogenous body, to which he gave the name cerealin, and which is closely allied in composition and action to the diastase of malt. Cerealin exerts a peculiarly energetic influence on starch, transforming it into a brown adhesive mixture of dextrin and sugar. He showed that when the fermentative action of gluten preponderates, the result is the formation of the products

desired by the baker-carbonic acid and alcohol; but when the influence of cerealin prevails, lactic fermentation ensues, and dextrin, sugar, and acid substances are formed, which it is the object of the baker to avoid. Several methods of avoiding this deteriorating influence of cerealin, and at the same time securing the use of the maximum of flour, have been put in operation by M. Mège Mouriès. The process now in use at the Boulangerie Centrale de l'Assistance Publique (the Scipion) in Paris, for the preparation of the flour and baking white bread with the whole of the mill products excepting the bran, he thus describes:-"The corn is moistened with from 2 to 5 per cent. of water saturated with sea-salt, and at the end of some hours the exterior coverings only become moist and tender. The grain is then thrown between nearly closed millstones, and 70 per cent. of flour is obtained without cerealin, plus 10 to 14 per cent. of meal. This is bruised between light stones, and separated by winnowing from the greater part of the husk remnants. To prepare the bread, all the leaven is made with flour at 70 per cent., and the meal is added to the soft dough last of all; as, in spite of the small amount of cerealin which it still contains, it will not produce brown bread, because at that time the length of incubation is not sufficient to change it into a leaven. Thus white bread is produced containing all the farinaceous part of the wheat."

It not unfrequently happens that flour of good color, and unexceptionable chemical composition, fails to yield a dough which will rise by fermentation, and the loaf from which is sweet, solid, sodden, and adhesive. Wheat that has been badly harvested, or which in any way has been allowed to sprout, has part of the gluten changed into the form of diastase, which, like cerealin, changes starch into dextrin and sugar. The gluten of flour which has been dried at a too high temperature, and of flour which has been kept in a damp situation, is modified and acts in the same manner. If dough is made with an infusion of malt, it yields a result exactly the same as that above de- | scribed. It is to guard the starch of inferior flour against this deteriorative influence that a proportion of alum is used by many bakers of second-class bread. Alum has the power of preserving starch to a large extent from the metamorphic action of altered gluten, diastase, or cerealin, and of producing from an inferior flour a loaf of good texture and color. The use of alum is regarded as an adulteration, and heavy penalties have been imposed on its detection; but its estimation in bread is a process of the greatest difficulty, and authorities are by no means agreed as to its deleterious influence. Other mineral salts have a similar protective power on the starch of inferior wheat, and lime-water has been successfully employed in place of alum. To this also it is objected by some that the addition of lime renders the valuable phosphatic salts of flour insoluble by transforming them into phosphate of lime.

Aerated Bread.-When carbonic acid, instead of being generated by fermentation within dough, is separately prepared and incorporated with flour and water, aërated bread is produced. The system by which this is effected was invented by the late Dr. Dauglish, and aërated bread has been manufactured under his patent since March, 1859. The system is now in operation in all the principal towns in the United Kingdom, and it appears to be steadily gaining in public favor.

The Dauglish apparatus (see fig. 3) consists of the following parts: 1st, a generator A, in which carbonic acid is evolved from chalk by sulphuric or hydrochloric acid; 2d, a gas-holder, in which the carbonic acid is stored for use after being purified in passing through water; 3d, an air-pump, for pumping carbonic acid from the gas-holder, and forcing it into the water vessel and mixer; 4th, another air-pump, for withdrawing atmospheric air from the mixer before the aërated water is admitted; 5th, a water vessel B, a strong cylinder of copper capable of withstanding a pressure of 100 lb on the square inch, and of sufficient size to contain water for a full charge of the mixer; attached to this water vessel there are a gaugeglass C, and a pressure gauge D, for indicating the pressure of gas as it is pumped in; 6th, the mixer E, a globular vessel of cast-iron, capable of bearing high pressure, through the centre of which an axle runs, fitted with iron kneadingarms extending to the circumference of the vessel. The pumps and the revolving arms within the mixer are worked

by steam power. In order to make a sack of flour into dough, a lid at the top of the mixer is opened, and the flour passed down into it through a spout from the floor above. The lid of the mixer is then fitted tightly on, and the air within it exhausted by the pump. The requisite quantity of water, about 17 gallons, is drawn into the water vessel, and carbonic acid is forced into it, till the pressure amounts to from 15 to 25 lb per square inch. The aërated water is then passed into the mixer, and the mixing arms are set in motion, by which, in about seven minutes, the flour and water are incorporated into a perfectly uniform paste. At the lower end of the mixer a cavity F is arranged, gauged to hold sufficient dough for a 2-tb loaf, and by a turn of a lever that quantity is dropped into a pan ready for at once depositing in the oven. The whole of these operations can be per formed in less than half an hour. When 4-lb loaves

FIG. 3.-Dauglish Apparatus-double set.

are to be baked the lever has simply to be twice turned. At another part of the lower end of the mixer is placed a pipe G, with a stop-cock, by which dough intended, to be fired as Paris bread, on the sole of the oven, is drawn off and weighed before being placed in the oven. The pressure of gas within the mixer is sufficient to force out the whole of the dough, which, immediately on being liberated, swells up by expansion of the gas confined within the tenacious mass. Currant loaves and various kinds of fancy bread are made by the aërated process by placing the necessary ingredients in the mixer along with the flour. The advantages claimed for Dr. Dauglish's process are:

"(1.) It does away entirely with fermentation, and with all those chemical changes in the constituents of the flour which are consequent upon it.

of the portion of starch or glucose consumed in the process of "(2.) It avoids the loss consequent upon the decomposition fermentation, estimated at about from 3 to 6 per cent.

"(3.) It reduces the time requisite to prepare a batch of dough for the oven, from a period of from eight to twelve hours to less than thirty minutes.

"(4.) Its results are absolutely certain and uniform.

66

(5.) It does away with the necessity for the use of alum with poor flour, and the temptation which bakers are under to use it

with all.

"(6.) It has the recommendation of absolute and entire cleanliness, the human hand not touching the dough or the bread from the beginning to the end.

destructive to their health-that of inhaling the flour dust in "(7.) The journeymen are relieved from a circumstance most the process of kneading. . . .

66

"(8.) It will produce a healthier condition of the baking trade, and thereby diminish to a great extent the inducements which lead to the extensive system of fraud now practised upon the public by the production of adulterated and inferior bread. (9.) It will effect an immense saving in the material from another source, namely, by preventing the sacrifice of at least 10 per cent. in the nutritive portion of the grain, hitherto lost as human food by the method of grinding and dressing necessary in the preparation of flour for making white bread

by fermentation.

"(10.) Together with the preservation of this large proportion of the entire quantity of wheat converted into flour, there is also the important result of the proportion preserved (the cerealin) being a most powerful agent in promoting the easy and healthy digestion of food."

It is objected by opponents of the Dauglish system that the product is not really bread, but only an artificial product resembling bread. It is held that the process of fermentation has a specific influence on the constitution of bread, beyond its mechanical effect of rendering the mass spongy or porous. One of the chief hindrances to the more general use of aërated bread is the fact that it is, as compared with fermented bread, insipid and tasteless. In practice, the public have not hitherto derived any advantage from the alleged economy of manufacture, and the suitability of inferior and cheap flour for the process. Although fermented bread is hurtful in some conditions, it is not easy to supplant well-made fermented loaves in general public estimation, and aërated bread can scarcely be said to have hitherto had a fair trial, as with the necessarily expensive machinery a large trade is necessary in order to return a fair profit on the capital invested.

Unfermented Bread.-Under this head is included such bread as is vesiculated by means of carbonic acid evolved from chemical substances introduced in the making of the dough. In writing the article on "Baking" for the supplement to the fifth edition of this Encyclopædia, published in 1816, Professor Thomas Thomson of Glasgow stated that the only end served by fermentation was the generation of carbonic acid gas, and that this might be accomplished by the use of hydrochloric acid and bicarbonate of soda. About 1842 Mr. Henry Dodson commenced to manufacture bread on this system, and obtained a patent for his process. He used hydrochloric acid and bicarbonate of soda in such proportions that while, by their reaction, they liberated sufficient carbonic acid to aërate the dough, they formed chloride of sodium or common salt enough for the bread. Liebig, in his Familiar Letters, says regarding this system:-"Chemists, generally speaking, should never recommend the use of chemicals for culinary preparations, for chemicals are seldom met with in commerce in a state of purity. Thus, for example, the muriatic [hydrochloric] acid which it has been proposed to mix with carbonate of soda in bread is always very impure, and very often contains arsenic." The sesquicarbonate of ammonia is also used as a source of carbonic acid in vesiculating bread, and it, on account of its highly volatile nature, is entirely driven off in the process of baking. A great amount of private or domestic baking is conducted on the same principle, butter milk and bicarbonate of soda being used for mixing the dough in making "scones." In this case the lactic acid of the milk combines with the soda, liberating carbonic acid. The baking powders and yeast powders which are sold, and the so called self-raising flour, all depend for their action on the mixture of bicarbonate of soda with some organic acid, such as tartaric or citric acid.

Baking Machinery and Ovens.-The art of baking, Machinery. although it is the most important of all industries connected with the preparation of human food, is one which is still carried on in the most rude and primitive manner. While modern inventions and the progress of improvement have changed the conditions under which nearly all arts and manufactures are conducted, the baking of bread is still conducted as it was during the palmy days of ancient Greece. The nature of the processes necessary for the preparation of bread, the limited time it will keep, and the consequent impossibility of storing the product or sending it any considerable distance, tend to keep the trade in the position of a limited and local handicraft. It is, therefore, not a pursuit which attracts capitalists, and master bakers are mostly in the position of small tradesmen, without either the inclination or ability to invest money in expensive machinery and fittings. In the case of biscuit-baking the conditions are quite different, and it, as has been seen, has developed into a great manufacture, with elaborate and complex machinery and the most perfect mechanical appliances. Many forms of machine have been proposed as substitutes for the rude and laborious manual laboralways unfavorable to health, and sometimes not very cleanly -involved in baking. Many of these machines admittedly produce better bread than can be made by handwork, and that at no inconsiderable saving of material and time, but the necessity of either steam or water power for their effective working greatly restricts their use.

The two processes to which machinery has been success

fully adapted, are the mixing of the sponge and the kneading of the dough. Attempts have been made to mould loaves by machinery, but these have hitherto failed; nor has the endeavor to fire bread in travelling ovens yet been practically successful. A great variety of kneading machines have been suggested and used, since the first trial of such an implement in Paris upwards of a century ago. The various plans upon which such machines have been constructed will be seen in the accompanying illustrations. Fig. 4 is a form of dough-making machine in common use. It consists of a trough or box, the lower portion of which is semi-cylindrical, hung on a spindle, with a series of iron crossbars revolving inside. It is

FIG. 4.-Kneading Machine.

made to be worked by either hand or steam-power, and of various sizes, as required by bakers. In this machine the whole of the operations connected with setting the sponge, breaking the sponge, and mixing the dough, are performed. The gearing is arranged to give a fast motion for setting the sponge, and a slow motion towards the close of the dough making, when it is desirable to draw out the mass in order to give it a "skin," or smooth superficial texture. A worm-wheel, working in toothed gearing, tilts over the machine when the process of kneading is complete, and the dough is then conveyed to the scaling and moulding table. Fig. 5 represents a kneading-machine, of a highly approved form, used in the great Scipion bakery of Paris, the invention of M. Boland. Externally it is like the former, and

FIG. 5.-Boland's Kneading Machine.

it is also geared to move at two rates of rapidity. It has further an adjustment by which the force of the motion is increased while its rate is diminished. The main peculiarity of M. Boland's pétrin méchanique consists in the form of the revolving blades inside the trough. These blades are so arranged that they operate when in motion somewhat like alternate screws, and so toss backward and forward the dough when it is thin, and lift and draw it out when stiff, passing it to each side of the trough alternately. An entirely different form of kneader is seen in fig. 6 This also is of French origin, the invention of M. DeliryDesboves of Soissons (Aisne). Its construction and operation are thus described:-"The trough is a cast-iron basin, which turns on a vertical axis. The interior is