ever may appear that is pernicious. There is no other time in all the day when competent guidance can do so much to make boys manly and girls womanly as when they are at their games. It is not enough to leave the play-ground to the janitor or to some inferior authority; it is the place where the principal teacher and nearly all the others are most needed-not to direct the games, or to meddle in any way with the sports, but to be ready with a cheery voice and an easy grace to suggest to any one about to engage in anything improper that he has forgotten himself. Ruffianism will soon disappear, timid children will learn to assert themselves, and an esprit de corps of the play-ground can soon be formed which will have a wonderful influence on the characters as well as the actions of the pupils. Nor is the benefit to the pupils all that is derived from this plan; the teacher needs such a recess quite as much as, and in many cases more than, her pupils. Fifteen minutes of each ninety in the open air, away from the sights and thoughts of the lessons, will remove the nervous, tired, irritable, and almost despondent feeling experienced by many teachers, and give them renewed strength and cheerfulness and mental elasticity for the remainder of the session. By being upon the playground among her pupils, many a teacher learns their character, their ambitions, the bent of their minds, as she can not learn them in the peculiar position in the school-room; and yet there are many children who, unless understood in these particulars, can not be successfully taught. To the teacher who sees her pupils only in their relation of pupils, the school-work is very likely to become a grind, a machine at which she is to perform a regular and a constant part, and the children are little else than so much raw material which is to pass through the mill over which she presides. She sees no individuality in them, and of course her work is arranged for the aggregate, and individuals receive no consideration as such. To overcome this error there is nothing better than for her to see them daily at their sports, for there their distinctive characteristics are manifested as in no other place. If the schools are to build character, certainly an out-door recess is an absolute essential for both teacher and pupils.

THE CHEMISTRY OF COOKERY.

By W. MATTIEU WILLIAMS.

XVI.

A CORRESPONDENT of Manchester asks me which is the most

nutritious, a slice of English beef in its own gravy, or the browned morsel as served in an Italian restaurant with the burntsugar addition to the gravy?

This is a very fair question, and not difficult to answer. If both are equally cooked, neither over-done nor under-done, they must contain, weight for weight, exactly the same constituents in equally digestible form, so far as chemical composition is concerned. Whether they will actually be digested with equal facility and assimilated with equal completeness depends upon something else not measurable by chemical analysis, viz., the relish with which they are respectively eaten. To some persons the undisguised fleshiness of the English slice, especially if under-done, is very repugnant. To these the corresponding morsel, cooked according to Francatelli rather than Mrs. Beeton, would be more nutritious. To the carnivorous John Bull, who regards such dishes as "nasty French messes" of questionable composition, the slice of unmistakable ox-flesh from a visible joint would obtain all the advantages of appreciative mastication and that sympathy between the brain and the stomach which is so powerful that, when discordantly exerted, may produce the effects that are recorded in the case of the sporting traveler who was invited by a Red Indian chief to a "dog-fight," and ate with relish the savory dishes at what he supposed to be a preliminary banquet. Digestion was tranquilly and healthfully proceeding, under the soothing influence of the calumet, when he asked the chief when the fight would commence. On being told that it was over, and that in the final ragoût he had praised so highly the last puppy-dog possessed by the tribe had been cooked in his honor, the normal course of digestion of the honored guest was completely reversed.

Reverting to the fat used in frying, and the necessity of its purification, I may illustrate the principle on which it should be conducted by describing the method adopted in the refining of mineral oils, such as petroleum or the paraffin distillates of bituminous shales. These are dark, tarry liquids of treacle-like consistency, with a strong and offensive odor. Nevertheless, they are, at but little cost, converted into the "crystal-oil" used for lamps, and that beautiful pearly substance, the solid, translucent paraffin now so largely used in the manufacture of candles. Besides these, we obtain from the same dirty source an intermediate substance, the well-known "vaseline," now becoming the basis of most of the ointments of the pharmacopoeia. This purification is effected by agitation with sulphuric acid, which partly carbonizes and partly combines with the impurities, and separates them in the form of a foul and acrid black mess, known technically as "acid tar." When I was engaged in the distillation of cannel and shale in Flintshire, this acid tar was a terrible bugbear. It found its way mysteriously into the Alyn River, and poisoned the trout; but now, if I am correctly informed, the Scotch manufacturers have turned it to profitable account.

Animal fat and vegetable oils are similarly purified. Very objectionable refuse fat of various kinds is thus made into tallow, or mate

rial for the soap-maker, and grease for lubricating machinery. Unsavory stories have been told about the manufacture of butter from Thames mud or the nodules of fat that are gathered therefrom by the mud-larks, but they are all false. It may be possible to purify fatty matter from the foulest of admixtures, and do this so completely as to produce a soft, tasteless fat, i. e., a butter substitute, but such a curiosity would cost more than half a crown per pound, and therefore the market is safe, especially as the degree of purification required for soap-making and machinery-grease costs but little, and the demand for such fat is very great.

These methods of purification are not available in the kitchen, as oil of vitriol is a vicious compound. During the siege of Paris some of the Academicians devoted themselves very earnestly to the subject of the purification of fat in order to produce what they termed "siegebutter" from the refuse of slaughter-houses, etc., and edible salad oils from crude colza oil, the rancid fish oils used by the leather-dresser, etc. Those who are specially interested in the subject may find some curious papers in the "Comptes Rendus" of that period. In vol. lxxi, page 36, M. Boillot describes his method of mixing kitchen-stuff and other refuse fat with lime-water, agitating the mixture when heated, and then neutralizing with an acid. The product thus obtained is described as admirably adapted for culinary operations, and the method is applicable to the purpose here under consideration.

Further on in the same volume is a "Note on Suets and Alimentary Fats" by M. Dubrunfaut, who tells us that the most tainted of alimentary fats and rancid oils may be deprived of their bad odors by "appropriate frying." His method is to raise the temperature of the fat to 140° to 150° Centigrade (284° to 302° Fahr.) in a frying-pan; then cautiously sprinkle upon it small quantities of water. The steam carries off the volatile fatty acids producing the rancidity in such as fish-oils, and also the neutral offensive fatty matters that are decomposed by the heat. In another paper by M. Fua this method is applied to the removal of cellular tissue of crude fats from slaughterhouses. It is really nothing more than the old farm-house proceeding of "rendering" lard, by frying the membranous fat until the membranous matter is browned and aggregated into small nodules, which constitute the "scratchings "—a delicacy greatly relished by our British plowboys at pig-killing time, but rather too rich in pork-fat to supply a suitable meal for people of sedentary vocations.

The action of heat thus applied and long continued is similar to that of the strong sulphuric acid. The impurities of the fat are organic matters more easily decomposable than the fat itself, or, otherwise stated, they are dissociated into carbon and water at about 300° Fahr., which is a lower temperature than that required for the dissociation of the pure oil or fat (see No. 13 of this series). By maintaining this temperature, these compounds become first caramelized, then carbon

ized nearly to blackness, and all their powers of offensiveness vanish, as such offense is due to slow decomposition of the original organic compounds, which now exist no longer, and the remaining caramel or carbon cinders being quite inoffensive or no further decomposable by atmospheric agency.

In the more violent factory process of purification by sulphuric acid the similar action which occurs is due to the powerful affinity of this acid for water; this may be strikingly shown by adding to thick sirup or pounded sugar about its own bulk of oil of vitriol, when at marvelous commotion occurs, and a magnified black cinder is produced by the separation of the water from the sugar.

The following simple practical formula may be reduced from these data. When a considerable quantity of much-used frying fat is accumulated, heat it to about 300° Fahr., as indicated by the crackling of water when sprinkled on it, or, better still, by a properly constructed kitchen thermometer graduated to about 400° Fahr. Then pour the melted fat on hot water. This must be done carefully, as a large quantity of fat at 400° poured upon a small quantity of boiling water will illustrate the fact that water when suddenly heated is an explosive compound. The quantity of water should exceed that of the fat, and the pouring be done gradually. Then agitate the fat and water together, and, if the operator is sufficiently skillful and intelligent, the purification may be carried further by carefully boiling the water under the fat, and allowing its steam to pass through; but this is a little dangerous, on account of the possibility of what the practical chemist calls "bumping," or the sudden formation of a big bubble of steam that would kick a good deal of the superabundant fat into the fire.

Whether this supplementary boiling is carried out or not, the fat and the water should be left together to cool gradually, when a dark layer of carbonized impurities will be found resting on the surface of the water, and adhering to the bottom of the cake of fat. This may be peeled off and put into the waste grease-pot, to be further refined with the next operation. Ultimately the worst of it will sink to the bottom of the water. Then it is of no further value, and will be found

to be a mere cinder.

XVII.

Regarding the fat used in frying as a medium for conveying heat, freedom from any special flavor of its own is a primary desideratum. Olive-oil of the best quality is almost absolutely tasteless, and, having as high a boiling-point as animal fats, it is the best of all frying media. In this country there is a prejudice against the use of such oil. I have noticed at some of those humble but most useful establishments where poor people are supplied with penny or twopenny portions of good fish, better cooked than in the majority of "eligible villa residences," that

in the front is an inscription stating that "only the best beef-dripping is used in this establishment.' This means a repudiation of oil. Such oil as has been supplied for fish-frying may well be repudiated.

On my first visit to arctic Norway I arrived before the garnering and exportation of the spring cod harvest was completed. The packet stopped at a score or so of stations on the Lofodens and the mainland. Foggy weather was no impediment, as an experienced pilot free from catarrh could steer direct to the harbor by "following his nose." Huge caldrons stood by the shore in which were stewing the last batches of the livers of cod-fish caught a month before and exposed in the mean time to the continuous arctic sunshine. Their condition must be imagined, as I abstain from description of details. The business then proceeding was the extraction of the oil from these livers. It is, of course, "cod-liver oil," but is known commercially as "fish-oil," or "cod-oil." That which is sold by our druggists as cod-liver oil is described in Norway as "medicine-oil," and though prepared from the same raw material, is extracted in a different manner. Only fresh livers are used for this, and the best quality, the "cold-drawn" oil, is obtained by pressing the livers without stewing. Those who are unfortunately familiar with this carefully prepared, highly refined product, know that the fishy flavor clings to it so pertinaciously that all attempts to completely remove it without decomposing the oil have failed. This being the case, it is easily understood that the fish-oil stewed so crudely out of the putrid or semi-putrid livers must be nauseous indeed. I am told that it has nevertheless been used by some of the fish-fryers, and I know that refuse "Gallipoli" (olive-oil of the worst quality) is sold for this purpose. The oil obtained in the course of salting sardines, herrings, etc., has also been used.

Such being the case, it is not surprising that the use of oil for frying should, like the oil itself, be in bad odor.

I dwell upon this because we are probably on what, if a fine writer, I should call the "eve of a great revolution" in respect to frying media.

Two new materials, pure, tasteless, and so cheap as to be capable of pushing pig-fat (lard) out of the market, have recently been introduced. These are cotton-seed oil and poppy-seed oil. The first has been for some time in the market offered for sale under various fictitious names, which I will not reveal, as I refuse to become a medium for the advertisement of anything-however good in itself—that is sold under false pretenses. If the lamp of KNOWLEDGE, more fortunate than that of Diogenes, should light upon some honest men who will retail cotton-seed oil as cotton-seed oil, I shall gladly (with the editor's permission) do a little straightforward touting for them, as they will be public benefactors, greatly aiding the present movement for the extension of the use of fish-food.

As

every bale of cotton yields half a ton of seed, and every ton of