introduction of the roller mill and middlings purifier. Formerly two

horizontal disk-shaped stones or burrs were employed, the lower one stationary and the upper one revolving in a horizontal plane and crudely crushing the grain between them. In all modern mills these have been entirely displaced by porcelain rolls revolving on horizontal axes and crushing the grain between them. The first of these roller mills is shown in pat. No. 182,250, to Wegmann, Sept. 12, 1876. (See Fig. 164). The outer rolls _d e_ are pressed against the inner ones _a c_ by a system of weighted levers, and scrapers below remove the crushed grain from the periphery of the rolls. Many subsequent improvements have been made, one type of which employs a succession of rolls which act in pairs on the grain one after the other and reduce it by successive gradations. [Illustration: FIG. 165.--MIDDLINGS PURIFIER.] The _middlings purifier_, see Fig. 165, comprehends a flat bolt or shaker screen _b_, of bolting cloth, arranged as a horizontal partition in an enclosing case through which passes an upward draft of air produced by suction fan D at the top. This air passing up through the bolting screen lifts the bran specks and fuzz from the shaken material as it passes downward through the screen, brushes K being arranged below to keep the screen constantly clean. A representative and pioneer type of this machine is seen in Pat. No. 164,050 to George T. Smith, June 1, 1875, from which the view is taken. The useful effect of the roller mill and middlings purifier is to save the most nutritious and valuable part of the grain, which lies between the outer cuticle and the white starch within, and which breaks up in fine grains and is of a golden hue. This portion of the grain was formerly unseparated, and was mixed with the middlings and bran as an inferior product. Modern analysis has disclosed its superior food value, and the roller mill and middlings purifier have provided means by which it can be separated from the bran and incorporated with the flour, thereby greatly adding to its wholesome character and nutritive value, and imparting to the flour the rich creamy tint which characterizes all higher grades. Minneapolis, Minn., is the great center of the milling interests of the United States. The Pillsbury Mills are located there, and the “Pillsbury A.” which is said to be the largest in the world, has a capacity of 7,000 barrels per day. In 1877-78 disastrous flour dust explosions at Minneapolis brought about the development of the dust collector, for withdrawing from the air of the mills the suspended particles of flour dust, which not only invited explosion, but rendered the air unfit to breathe. Washburn’s Pat. No. 213,151, March 11, 1879, is an early example. The use of crushing rolls has also developed a great variety of new foods, such as cracked wheat, oatmeal grits, etc. These crushing rolls have sometimes been made hollow, and are steam heated, and as they crush the grain they simultaneously effect the cooking or partial conversion of the starch, and the product is known as hominy flake, ceraline, coralline, etc., which furnish popular breakfast foods when served with cream. [Illustration: FIG. 166.--DOUGH MIXER.] [Illustration: FIG. 167.--BRAKE, OR KNEADING MACHINE.] In the field of cookery such activity has been displayed that the average kitchen to-day is a veritable museum of modern inventions. Egg beaters, waffle irons, toasters, broilers, baking pans, apple parers, cherry stoners, cheese cutters, butter workers, coffee mills, corn poppers, cream freezers, dish washers, egg boilers, flour sifters, flat irons, knife sharpeners, can openers, lemon squeezers, potato mashers, meat boilers, nutmeg graters, sausage grinders, and frying pans in endless array; all patented and clustered around the modern cooking range as a central figure, and all presenting points of excellence in the matter of economy and convenience, or the betterment of result. The most extensive application of inventive genius is to be found in the large manufacturing bakeries, which make and sell the millions of pounds of crackers and cakes that fill the bins and shelves of the grocery store. In these manufactories the dough is prepared by a mixer, see Fig. 166, which consists of a spiral working blade revolving in a trough, and capable of handling half a dozen barrels of flour at a time. It is then put through a kneading machine, called a “brake,” shown in Fig. 167, and is then ready to be converted into crackers or cakes on a great machine 25 feet long, which finishes the crackers and puts them in the pan ready for the oven. This machine, see Fig. 168, receives the dough at A, where it is coated with flour and flattened into a sheet between rolls. It is then received on a traveling apron B, has the flour brushed off by a rotary brush C, and is then cut into crackers or cakes by vertically reciprocating dies D. At E a series of fingers press the cakes down through the sheet of dough, while the surrounding scraps are raised on a belt F and delivered into a suitable receptacle. The separated cakes at B′ are then delivered into pans at G, the pans being fed on the subjacent belt at G′. Such machines, costing nearly a thousand dollars, produce from forty to sixty barrels of crackers a day, enabling them to be sold at about 5 cents a pound at retail. [Illustration: FIG. 168.--CRACKER AND CAKE MACHINE.] _Dairy Appliances_ have come in for a large share of attention at the hands of the Nineteenth Century inventor. There are about sixteen million milch cows in the United States, and their contribution to the food stuffs of the day in milk, butter, and cheese is no insignificant factor. There have been over 2,700 patents granted for churns alone, and besides these there are milk coolers, cheese presses, milk skimmers, and even cow milkers. The centrifugal milk skimmer is an interesting type of this class of machine. In the old way the milk was set for the cream to rise, which it did slowly from its lighter specific gravity. In the centrifugal skimmer the milk is continuously poured in through a funnel, and the cream runs out continuously through one spout, and the skimmed milk at the other. An illustrative type of this machine is shown in Fig. 169. A steam turbine wheel near the base turns a vertical shaft bearing at its upper end a pan which rotates within the outer case. The milk enters through the faucet at the top, and as the pan within rotates, the heavier milk, by its greater specific gravity, is thrown to the outer part of the pan and passes out through the larger of the two spouts, while the lighter cream is crowded to the center and passes out of the upper spout, which opens into the center of the pan. Patents to Lefeldt & Lentsch, No. 195,515, Sept. 25, 1877, and Houston and Thomson, No. 239,659, April 5, 1881, represent pioneer milk skimmers of this type. [Illustration: FIG. 169.--CENTRIFUGAL MILK SKIMMER.] Closely allied to the dairy appliances are the incubator and the bee hive, both of which have claimed a large share of attention, and for which many patents have been granted. One important and characteristic feature of the present age is the conservation of waste in perishable foodstuffs. Fruits, vegetables, fish and oysters were suitable food to our forefathers only when freshly taken, and any superabundance in supply was either wasted by natural processes of decay, or was fed to the hogs. To-day thousands of patented fruit dryers, cider mills, and preserving processes save this waste and carry over for valuable use through the unproductive winter months these wholesome and valuable articles of diet. Even more important is the _canning industry_, by which not only fruits are maintained in a practically fresh condition for an indefinite time, but oysters, meats, fish, soups, and vegetables are also put up in enormous quantities. To-day the grocer’s shelves present an endless array of canned tomatoes, peaches, corn, peas, beans, fish, oysters, condensed milk, and potted meats, which constitute probably three-fourths of his staple goods. The tin can is in itself a very insignificant thing, not entitled to rank with any of the great inventions, but in the every-day campaign of life it is playing its part, and working its influence to an extent that is little dreamed of by the casual observer. It renders possible our military and exploring expeditions; it holds famine and starvation in abeyance; it gives wholesome variety to the diet of both rich and poor; and it transfers the glut of the full season to the want of future days. Perhaps no single factor of modern life has so great an economic value. Simple as is the tin can, quite complex machines are required to make it. Originally such machines were operated by hand or foot power, but within the last 25 years power machines have been devised which automatically convert a simple blank or plate of sheet metal into a finished can. Of the many patents granted for such machines the most representative ones are 243,287, 250,096, 267,014, 384,825, 450,624, 465,018, 480,256, 495,426, 489,484. In the process of putting up canned goods the products are filled into the cans, and the caps, or heads, are soldered on. These caps have a minute hole in the center for the escape of air and steam in the process of cooking and sterilizing, which is conducted as follows: A large number of cans are placed on a tray swung from a crane and the cans lowered into one of a series of great cooking boilers. The cover of the boiler is then closed and fastened by lugs, and steam turned on until the goods in the can are thoroughly heated through. During this process the air and steam escape through the little vent hole from the interior of each can. The cans are then removed, the vent hole closed by a drop of solder, and the goods thus hermetically sealed in a cooked or sterilized condition will keep for a long period of time. _Sterilizing._--During the last quarter of the century, which has witnessed the growth of the wonderful science of bacteriology, a class of devices known as sterilizers has come into existence, whose primary function is to kill the germs of decay by heat. This has had in the canning industry an important commercial application. An example is found in the patent to Shriver, No. 149,256, March 31, 1874. In some of these devices the receptacles containing the food stuffs are in large numbers placed within the heating chamber, and by devices operated from the outside the cans or bottles are opened and shut while within the steam filled chamber. A late illustration is found in patent to Popp _et al._, 524,649, August 14, 1894. _Butchering and Dressing Meats._--Chicago is the leading city of the world in this industry, and Armour & Co. the largest packers. In the year ending April 1, 1891, they killed and dressed 1,714,000 hogs, 712,000 cattle, and 413,000 sheep. They had 7,900 employees, and 2,250 refrigerating cars were employed for the transportation of their products. The ground area covered by their buildings was fifty acres, giving a floor area of 140 acres, a chill room and cold storage area of forty acres, and a storage capacity of 130,000 tons. In addition to its meat packing business the firm has separate glue works, with buildings covering fifteen acres, where 600 hands are employed, their production in 1890 being 7,000,000 pounds of glue, and 9,500 tons of fertilizer. Since 1891 this great business has increased until to-day it is said that the army of workmen employed is greater than that of Xenophon, that the firm pays out in wages alone, half a million dollars every month, that four thousand cars are required to carry the products of their factory, and whose business amounts to the enormous sum of one hundred million dollars annually. [Illustration: FIG. 170.--KILLING AND DRESSING PORK.] There are from forty to fifty million cattle raised in the United States, and an equal amount of sheep. The number of hogs raised has diminished somewhat in the past few years, but from 1889 to 1892 more than fifty million were maintained. The process of slaughtering and dressing pork, as practiced to-day, is a continuous one, and is well illustrated in Fig. 170, in 13 operations. The animals are driven into a catching pen at 1, where they are strung up by one leg, and secured to a traveling pulley on an overhead rail. At 2 the animal is instantly killed by a knife thrust that reaches the heart; at 3 he is dumped into a vat of scalding water, kept hot by steam pipes, where the hair is loosened (see detail view Fig. 171). A series of oscillating curved arms, shaped like a horse hay-rake, dips the carcass out of the scalding vat and deposits it upon the table 4 (Fig. 170), where it is attached to an endless cable that drags it through a scraping machine at 5. This takes off the hair, as shown in detail view Fig. 172. At 6 (Fig. 170) the remnants of hair are removed by hand, and at 7 the skin is washed clean. At 8 the carcass is inspected, and the throat cut across; at 9 the entrails are removed; at 10 the leaf lard is taken out; at 11 the heads are severed and tongues removed; at 12 the carcass is split into halves, and at 13 the sections are ready to be run into the cooling room. [Illustration: FIG. 171.--SCALDING TO LOOSEN THE HAIR.] [Illustration: FIG. 172.--SCRAPING OFF THE HAIR BY MACHINERY.] From 10 to 15 minutes only are required to convert the living animal into dressed pork. Every part of the animal is utilized. The lungs, heart, liver and trimmings go to the sausage department. The feet are pickled or converted into glue. The intestines are stripped and cleaned for sausage casings. The soft parts of the head are made into so-called cheese, and the fat is rendered into lard. The finer quality of bristles goes to the brushmakers, and the balance is used by upholsterers for mixing with horse hair. The blood is largely used for making albumen for photographic uses, as well as in sugar refining, for meat extracts, and for fertilizers. The bones are ground for fertilizer, and even the tank waters are concentrated and used for the same purpose. _Oleomargarine._--About 1868 M. Mege, a French chemist, commissioned by his government to investigate certain questions of domestic economy, was led into the study of beef fat, and to make comparisons of the same with butter. He found that when cows were deprived of food containing fat they still continued to give milk yielding cream or fatty products. He therefore concluded that the stored-up fat in the animal was then converted into cream, and that it was practicable, therefore, to convert beef fat into butter fat. Physiology taught that in the living animal the change was wrought through the withdrawal of the larger part of the stearine by respiratory combustion, while the oleomargarine was secreted by the milk glands, and its conversion into butyric oleomargarine effected in the udder under the influence of the mammary pepsin. In the process of making butter by the ordinary method of churning the cream, the finely divided butter fat globules are united into masses, containing by mechanical admixture from 12 to 14 per cent. of water or buttermilk carrying a fractional per cent. of cheese. This buttermilk contributes somewhat to the flavor, but at the same time furnishes a ferment which ultimately spoils the butter by making it rancid. It is a purely accidental ingredient, and one not at all desirable. To some extent the same may be said of the soluble fats which give to the butter its variable though characteristic flavor. They are unstable compounds, decomposing readily, and furnish the acrid products which make “strong” butter. M. Mege sought to imitate the natural process of butter-making, which was first to separate from the oily fat of suet the cellular tissue and excess of stearine or hard fat; second, to add to the oil a sufficient proportion of butyric compounds to give the necessary flavor, and third, to consolidate the butter fat without grain, and to add at the same time the requisite proportion of water, salt, and coloring matter, to make a compound substantially the same in composition, flavor, and appearance, as butter churned from the cream, and all this without adding to the original fat anything dietetically objectionable, and without submitting it to any process capable of impairing its wholesome quality. These objects were fairly obtained in the product known as oleomargarine, the United States patent for which was granted to Mege Dec. 30, 1873, No. 146,012. The process in brief is to take fresh beef fat, which is first chopped up and thoroughly washed. It is then placed in melting tanks at a temperature of 122° to 124° F, and the clear yellow oil is drawn off and allowed to stand until it granulates. The fat is then packed in cloths set in moulds and a slowly increasing pressure squeezes out the pure amber colored oil, leaving the stearine behind. This sweet and pure yellow oil is then churned with milk for 20 minutes until the oil is completely broken up, and a small quantity of annato, a vegetable coloring matter, is added to give a yellow color. The product is then cooled in ice, and after a second churning with milk it is salted and finished like butter. Chemical analysis shows oleomargarine to have substantially the same constituents and in almost the identical proportions of pure butter. It is equally wholesome, and while it does not have the same rich flavor, it has the advantage that it keeps better, and is not so liable to become rancid or strong. The oleomargarine industry is closely related to the beef packing industries of the United States, and its growth has been enormous. Notwithstanding the stringent laws on the subject, much of the oleomargarine made is sold for, and by the average purchaser is not distinguishable from, pure butter. In 1899 there were 80,495,628 pounds of oleomargarine made in the United States, or more than a pound for every man, woman, and child in the country. The internal revenue tax paid on it was $1,609,912.56. The exports for the year 1899 were 5,549,322 pounds of the artificial butter, and 142,390,492 pounds of the oleo oil prepared for conversion into the complete product by simply churning with milk. _Sugar._--Sugar-cane, beets, and the sap of the maple constitute the sources from which sugar is extracted, but the cane furnishes by far the largest supply. When crushed between rolls it yields 65 per cent. of its weight as juice, and 18 per cent. of this juice is sugar. It is concentrated by evaporation at a low temperature, the crystallized portion being known as “raw” or brown sugar, which is subsequently refined, while the uncrystallized portion forms molasses. [Illustration: FIG. 173.--VACUUM PAN FOR EVAPORATING THE SYRUP TO PRODUCE SUGAR.] In the process of refining, 2 or 3 parts of raw sugar, with one of water containing a little lime, ground bone black, and the serum of bullocks’ blood, is heated by the passage of steam through it. The albumen of the serum coagulates and rises to the surface in a scum which entangles the impurities and bone black, leaving the syrup light in color. The latter is then filtered through bone black until it is colorless and is then evaporated in the vacuum pan, which is the important invention of the century in sugar making. Heat has the effect of converting the crystallized sugar into the uncrystallized variety, and hence the evaporation must, to prevent this, be conducted at a low temperature. Contact with the air is also objectionable. These conditions are provided for by conducting the evaporation in a vacuum, which lowers the evaporating temperature and avoids contact with the air. The vacuum pan was the invention of Howard, an Englishman. (British Pat. No. 3,754, of 1813). As constructed to-day it is an enormous vessel (see Fig. 173), capable of holding 7,000 or more gallons, and yielding 250 barrels of sugar at a strike. In this a vacuum is maintained by a condenser, the vapors passing from the pan to the condenser through the great curved pipe rising from the top, which pipe is five feet in diameter. A gentle heat is applied through internal steam-heated coils which connect with an external series of steam inlet pipes on one side, and a corresponding series of steam outlet pipes on the other. A large discharge valve for the concentrated syrup closes the bottom of the pan. After concentration the crystallized sugar is separated from the syrup by a centrifugal filter, in which the liquid is thrown from the crystallized sugar by centrifugal action. The first centrifugal filter is shown in British patent to Joshua Bates, No. 6,068, of 1831. This, however, revolved about a horizontal axis. The present form of centrifugal filter is a cylinder revolving about a vertical axis, the sides of the cylinder being formed of filtering medium, through which the liquid is thrown by centrifugal action, while the sugar is retained within. This was the invention of Joseph Hurd, of Mass., U. S. Pat. No. 3,772, Oct. 3, 1844; re-issue No. 607, Sept. 29, 1858, which patent was extended for seven years, from Oct. 3, 1858. The diffusion process, which extracts the juice by cutting the cane in slices and soaking in water; the bagasse furnace, which dries and burns the expressed cane stalks as fuel, and the manufacture of glucose and grape sugar by the reaction of sulphuric acid on starch, are interesting allied features of this industry which can only be briefly mentioned. Most of the sugar consumed in the United States is imported, much raw sugar being imported and refined here. The imports for the year 1899 were 3,980,250,569 pounds, and the per capita consumption in 1898 was 61.1 pounds a year. _Aids to Digestion._--It is only during the last part of the Nineteenth Century that the world has learned how to live. “What is one man’s food is another man’s poison” has been a trite old saying for many years, but the reason why has only in late years been fully understood. The physiology of digestion, the relative digestibility of different articles of food, and their nutritive values, have received of late years the earnest attention of physicians and students of dietetics and have contributed much to the quality and kind of food, and a knowledge of when and how to eat it. We know that the starchy foods are digested by the saliva, which is an alkaline digestion; that meat, fish, eggs, cheese and the albumenoids are digested in the stomach by the gastric juices (pepsin and hydrochloric acid) which is an acid digestion, and that the remaining portions of starch, the sugars, and fats are digested in the intestines, and that this is also an alkaline digestion, and this has helped to solve the problem for us. We also know that starch is an excellent food, provided the vital powers are sufficiently stimulated by fresh air, sunlight, and exercise to digest it, as do the horse and the ox when they eat corn, but we know furthermore that the sedentary occupations of modern life leave many stomachs in a condition unable to assimilate starch, and so bread, oatmeal, potatoes and such simple staples, instead of nourishing the body, ferment in the enfeebled stomach, produce acids and gas, and lay the foundation for serious chronic diseases. The student of chemistry and dietetics knows to-day that one part of diastase will effect the conversion of 2,000 parts of starch into grape sugar, as a preliminary step to its digestion, and so by treating starchy matter with substances containing diastase (derived from malt) a partial transformation is effected which will materially shorten and assist its digestion. This fact has been largely made use of in the preparation of easily soluble or pre-digested foods, examples of which are found in patent to Horlick (malted milk), No. 278,967, June 5, 1883; to Carnrick (milk-wheat food), Dec. 27, 1887, No. 375,601; and Boynton and Van Patten (cereals and diastase), 344,717, June 29, 1886. _Beverages._--Pure water, nature’s own gift, has ever supplied every legitimate need of the human race, but civilized life has greatly extended its list of drinks, much to its own detriment. Soda water, whiskey, beer, ginger ale, tea, coffee, and chocolate represent enormous industries, and probably all do more harm than they do good. Much inventive genius in the Nineteenth Century has been bestowed upon the soda water fountain, on stills, and processes for aging liquors and processes for brewing beer, on cider and wine presses, on bottling machines and bottle stoppers, on devices for carbonating waters, and in coffee and teapots. The trend of the times is shown in the following figures, which represent the per capita consumption of beverages in the United States for 1898: tea, .91 of a pound; coffee, 11.45 pounds; wines, .28 of a gallon; distilled spirits, 1.10 gallons; and malt liquors 15.64 gallons. The largest per capita increase since 1870 has been in malt liquors, and the next in coffee. In tea and distilled spirits there has been a decrease, while the consumption of wines is the smallest of all and has varied but little.