plate is turned toward the front to protect it from being smoked, but when the fire is fairly burning, the plate is turned back at an angle of forty-five degrees, as indicated by the wheel on the side of the stove. The result is described about as follows: The reflection from the bright metallic surface produces the effect of a double fire, and adds greatly to its cheerfulness. In addition to this, it is claimed that the large amount of heat thus reflected by the plate is, to a great extent, a clear gain, and that the effect of its employment is readily perceived in increased warmth at quite a distance from its source. Furthermore, it is claimed that the rush of air usually passing up the chimney of an open stove or grate, and which makes this excellent form of heating apparatus so expensive in rapid consumption of fuel, is checked and thrown down on the fuel, producing surface combustion, while the draught at the base may be shut off, giving a clear, bright fire, without wasteful consumption of coal.-Iron Age, September 30.

METHOD OF COOLING THE AIR.

MM. Nezereaux and Garlandal have lately devised a proc ess of cooling and at the same time purifying the air introduced into dwellings for purposes of ventilation. It consists of a fan caused to revolve rapidly, by means of which the air is forced into a closed box, and made to pass through a horizontal diaphragm with holes, over which a very thin layer of water is continually flowing. The air, as it passes through this thin film of water from below, is deprived of its organic particles, which remain in solution in the water, which is continually dripping down into the lower chamber and drawn off, the air itself passing up and out through a pipe in any desired direction.-13 B, Dec. 18, 34.

IMPROVEMENT IN FIRE-PLACES.

Forestier describes an improvement in the ordinary fireplace, in which by contracting the smoke-flue for some distance above the fire-place, and by introducing side flues for the admission of fresh air, he is, he states, able to effect a very material economy in the consumption of coal; the fireplace as built by him, with an open basket grate, is superior to any of those described by Morian, Peclet, Grouvelle, and Clement. He finds that ordinary chimneys, producing the

same result as attained in his own, consume four times the quantity of fuel; and the comparison with even the most improved chimneys is always decidedly in his favor.-Memoirs Academy of Sciences, Toulouse, 1875, 233.

CHEAP SOAP FOR ORDINARY ARTICLES AND WOOLEN

FACTORIES.

Mayr recommends the following process for preparing a very cheap soap. First procure from a soap-boiler the spent lye or salt lye, either in a fluid or gelatinized condition, and preserve it in well-covered vessels until required. Prepare a soda lye of 22° Baumé, by heating in a boiler 100 pounds of calcined soda in about 52 gallons of water until it is dissolved. Add to this gradually 60 pounds of fresh, unslaked lime, stir the mixture well, and transfer the whole of it to a tub of sufficient size, and allow it to stand for about 12 hours, that the lime may settle. Then carefully dip out the lye from the lime into the kettle again, and boil until it indicates 22° Baumé. After cooling, transfer to a suitable vessel, and cover tightly. Then prepare a potash lye of 10° Baumé, by stirring potash into hot water, until the required strength is reached. As an experiment, boil 25 pounds of cocoa-oil with 30 pounds of potash lye of 10° Baumé, and add gradually, when not boiling too vigorously, 30 to 40 pounds of soda lye of 22° Baumé. After the combination of the oil and lye, and the mass has assumed the appearance of a brown glue, and is thready, add, with vigorous stirring, 159 pounds of spent lye of not over 16° Baumé, but diluted to this strength, if necessary, with lime-water. Boil the mass for half an hour, and allow the fire to die down. It will appear as fluid as water, and very unlike soap, but a sample, if allowed to cool perfectly on a board, or in a porcelain dish, will harden. The principal point at this stage is to transfer the mass to a tub, and allow it to cool, and on the following day to transfer it again to the boiler without the addition of any liquid, and after boiling it for an hour, samples will yield elastic threads indicative of increasing consistency. Then add common salt gradually, until a cooled sample feels dry upon the hand. Allow the fire to slacken, and ladle the mass into forms, which can be taken apart when the soap becomes hard. The advantage of this proc

ess is increased by repeated warming and cooling of the mass, as the proper consistency is thus hastened, and the quantity of soap increased. Cocoa-soap shavings may also be employed according to the fat they contain. If the spent lye is old, and has been exposed to the air, dilute 12 pounds of potash lye, of 22° Baumé, with lime-water to 10°, and boil it with the 25 pounds of cocoa-oil. The addition of a few pounds of crude palm-oil will impart to this soap a color similar to that of tallow soap.-26 C, II., 1876, 14.

CLOTH OF FEATHERS FOR LADIES' CLOAKS, ETC. The following are the essential features of a process, recently patented, for the manufacture of cloth, suitable for ladies' cloaks and all kinds of garments, from feathers, principally of water-fowls. As the down only can be employed, the material is assorted, according to its specific gravity, by a fanning-machine. Then, after being soaked in water containing Marseilles soap, and pressed out in a square box by aid of a screw, and separated again, and partially dried by means of the fan, it is oiled, and passed three times through the fanning-machine. A fleece of wool, formed on the usual carding-machine, is then covered loosely with four times its weight of the feathers, and these by another layer of wool. The rove is then formed in the usual way, provision being made to prevent two threads from uniting. In spinning a large hand machine is employed, instead of a self-actor. The weaving is accomplished in the usual way, except that, as a rule, warp of combed-wool yarn is preferred, although, according to the material, it may be of carded yarn, or even of carded yarn and feathers. The cloth is oiled, and fulled as usual, with care to dry after fulling. In dyeing a very large vat must be used, that the whole breadth of the piece may be immersed at a time. It is finally beaten and brushed to remove any feathers not fully incorporated with the wool, and a gloss is imparted to it by steaming.-23 C, Jan. 1,1876, 4.

COOKING MEAT BY COLD.

The generally accepted theory of the cooking of meat relates to the application of heat; but quite recently Dr. Sa wiczevosky has called attention to the fact that almost precisely the same chemical and physical changes can be ac

complished by the exposure of animal flesh to extreme cold. Indeed, the sensation experienced by touching freezing mercury is very much that of a severe burn. The experimenter referred to proposes to apply his method to the preservation of meats, first by subjecting them to a temperature of 33° Fahr. below zero, and then sealing them up hermetically in tin vessels. Animal substances, kept for a long time in these boxes, on examination proved to be extremely palatable, and, being partially cooked, required but a little additional heat to prepare them for the table.

The German government has lately been prosecuting investigations into this process as a means of preparing military and naval supplies, a large quantity suitably sealed being placed on board some vessels undertaking a long voyage, with a view of determining more definitely its availability for the purpose referred to. An establishment in Hungary is now engaged in the preparation of meats by this method on an extensive scale.-12 B, April 1, 1876, 286.

ANTISEPTIC ACTION OF SALICYLIC ACID.

In further continuation of his experimental trials of this substance, Dr. C. Neubauer affirms that salicylic acid will be of great value in the preservation of wines, but that it is adapted rather to prevent than to correct or cure morbid changes that have taken place therein.-4 B, Sept., 1876.

PRODUCTION OF MADEIRA WINE.

It is well known that for some years past Madeira wine has been almost unknown in the trade, on account of the extinction of the crop of the island consequent upon a long series of bad vintages. The old vineyards were rooted up, and new ones planted; but of course a long time would have to elapse before any great yield could be expected, and those having in their possession genuine Madeira held it as a great prize. The least period of production extended from 1853 to 1857; and from 1860 to 1862 but 500 pipes were produced. At present the production has risen to an average of 10,000 or 12,000 pipes, which is about one third that of former years. It is not thought, however, that the quantity will ever much exceed this, since a great deal of the island which formerly was planted with vineyards is now used for corn

and other crops, which are said to pay the proprietors better than wine.-17 A, XXI., 117.

CLEANING SILVER-WARE, ETC., WITH POTATO-WATER. Silver and plated articles should be placed about ten minutes in the hot water in which potatoes have been boiled (with salt), and then be rubbed with a woolen rag, and rinsed in pure water, when the articles will not only be free from tarnish, but perfectly bright. Potato-water that has become sour by standing several days answers still better, and is also excellent for cleaning articles of steel and glass waterbottles.-5 C, March, IV., 32.

SUBSTITUTE FOR PERSIAN INSECT-POWDER.

The wild rosemary (Ledum palustre) has been suggested as a substitute for Persian insect-powder. When dried as well as fresh it is destructive to lice, bugs, fleas, moths, etc. The tincture prepared from it is also a remedy for the bites of gnats, and insects generally; not only relieving the itching in a short time, but also the pain when applied to a wound. The tincture repels gnats when mixed with glyc erine and rubbed upon the skin. It seems to deserve notice on account of these properties, and its possible substitution for the more expensive and frequently adulterated Persian insect-powder. It is most effective when fresh and in bloom, and should be gathered in the latter condition.-5 C, 72.

DETECTION OF OLEOMARGARINE IN BUTTER.

According to Mr. Horsley, it is not difficult to determine by chemical tests the presence of oleomargarine, or artificial butter, as an adulteration in genuine butter. He remarks that fresh butter is completely soluble in methylated ether of specific gravity 0.730 at a temperature of 65°. If methylated alcohol, 63° above proof, be added to this, and well shaken, all the lard, beef, mutton, or tallow fats that may have been mingled with the butter will be precipitated. Care, however, is to be taken not to mistake the crystallization of butter out of the ethereal solution, at a lower temper ature than 65°, for the fats precipitated by the alcohol. The butter, besides, being so much lighter, occupies the upper layer, is different in character, and is easily remelted by the