English Mechanic, promises to be useful as a vehicle for emollient preparations. It is a solid, semi-transparent jelly, free from taste or odor, and becomes liquid at 93° Fahr. It is obtained by evaporating crude petroleum, and filtering the residue through animal charcoal.-18 A, Sept. 25, 1874, 36.

TINNING VARIOUS METALS IN THE HUMID WAY.

The following method is given by Wegler: A solution of perchloride of tin is first prepared by passing washed chlorine gas into a concentrated aqueous solution of tin-salt, and expelling the excess of chlorine by gently warming it, then diluting it with eight to ten times its volume of water, and filtering it, if necessary. The article, well pickled in dilute sulphuric acid, and polished with sand and a steel scratch-brush, and rinsed with water, is loosely wound with a zinc wire, and immersed for ten or fifteen minutes, at the ordinary temperature, in the dilute solution of perchloride of tin. When tinned in this way, it is rinsed, brushed with a scratch-brush, dried, and finally polished with whitening. This applies to tinning cast iron, wrought iron, steel, copper, brass, lead, and zinc.-13 C, November 1, 1874, 1368.

GILDING GLASS.

The following process for gilding glass has been patented by Professor Schwarzenbach: A filtered solution of perfectly pure chloride of gold, in boiling water, is diluted until twelve cubic inches of the liquid contain one grain of metallic gold, and is then rendered alkaline with caustic soda. As a reducing agent, alcohol saturated with marsh gas, and then. diluted with its volume of water, is employed. One and a half cubic inches of this liquid are added to the alkaline gold solution, and the mixture then poured between the plate to be gilded (previously well cleansed) and a glass plate placed about one tenth of an inch below it. After remaining undisturbed from two to three hours the gilding is complete, and the glass is removed and washed.-16 C, November 26, 1874, 428.

NEW PHOSPHOR-BRONZES.

Dr. Kunzel, whose name will be recalled as the joint discoverer, with M. Montefiore-Levy, of the well-known phos

phor-bronze, now announces the additional discovery that when phosphor-bronze is combined with a certain fixed proportion of lead, the phosphorized triple alloy, when cast into a bar or bearing, segregates into two distinct alloys, one of which is hard and tough phosphor-bronze, containing but little lead, and the other a much softer alloy, consisting chiefly of lead, with a small proportion of tin and traces of copper. The latter alloy is almost white, and, when the casting is fractured, it will be found nearly equally diffused through it; the phosphor-bronze alloy forming as it were a species of metallic sponge, all of whose cavities are occupied by the soft metal alloy segregated from it. This phenomenon of the segregation into two or more alloys, of combinations of copper with tin and zinc, has long been known, and from the fact that such separation is generally massive, and not equable throughout the mass, it has been a source of great annoyance to the founder. Dr. Kunzel, however, seems to have succeeded in causing the segregation to take place in uniform distribution throughout the casting, and has taken advantage of the properties of the product which he obtains in this manner to construct therefrom bearings of railway and other machinery.

In heavy bearings, such as those for marine engines, the valuable properties of Babbitt metal, and similar anti-friction alloys, are well recognized; but these being generally soft, are open to the grave objection that where they are subject. ed to considerable pressure, or even moderate pressure accompanied by continued vibration, they become distorted in form, and then fail to sustain the journals in their proper places. The device is, therefore, resorted to by the machinist of casting a hollow cage of hard metal, of proper form, for the intended bearing, the cavities of which he then fills by casting into them the soft metal alloy, which thus forms the actual rubbing surface of the bearing. The hard metal cage supports the soft metal within, and prevents its distor tion or escape, save by surface abrasion. Dr. Kunzel claims to effect the same result by the peculiar constitution of his new phosphorized alloy for bearings. This forms its own supporting cage, for the soft bearing metal, which, as alluded to at the outset, separates from it in the progress of cooling. He claims that these bearings combine the very small fric

tion and non-abrasion of the journals, with the firm resist ance to pressure and stability of form of bearings of hard metals. The test of practice alone can decide the value of these claims, though they seem very plausible.—3 A, October 24, 1874.

A NEW SILVER-LIKE ALLOY.

A new and inoxidizable alloy, resembling silver, has lately been patented by Le Marquand, of Paris, and has the following composition per kilogramme:

These different ingredients are to be melted together in a crucible.-9 B, May 6, 208.

PLATING WITH ALUMINIUM.

The following process for covering metal surfaces with aluminium is recommended by J. A. Jeancou: Dissolve any desired quantity of a salt of aluminium, such as sulphate, chloride, nitrate, cyanide, etc., in distilled water, and concentrate the solution to 20° Beaume (at 50° Fahr.) in a vessel suitable for holding the article to be plated. The battery to be used should either be four pairs of Smee's or three of Bunsen's, with the elements connected for intensity, and a plate of aluminium attached to the positive pole. The solution should be slightly acidulated with its appropriate acid, heated to 140° Fahr., and kept at that temperature during the operation.

MANUFACTURE OF STEARIC ACID.

In order to facilitate the removal of the oleic acid in the manufacture of stearic acid, Deisz suggests the addition of 20 per cent. of bisulphide of carbon to the mass before pressing, since but one pressing in the cold will then be required to remove the oleic acid thus diluted, and the bisulphide can easily be removed by distillation. The process is, however, considered objectionable by Professor Heeren, on account of the unavoidable loss of bisulphide, as well as the injurious

action of its vapor upon the operatives. He regards the idea, meantime, as a good one, and thinks the substitution of some less volatile and injurious liquid (as petroleum naphtha) for the bisulphide is well worth trying.-15 C, XVII., 1874, 272. GAUDIN'S POLISHING PAPER.

Messrs. Gaudin & Co., of Paris, have recently introduced a new polishing paper, made with a mixture of silex and alumina melted together and reduced to a fine powder. This they claim is much superior to emery paper or any other substance used for the same purpose. It really constitutes an artificial emery or corundum, but is in a form much more convenient for application than the natural substance.-1 B, May 2, 61.

PREPARATION OF ABSOLUTE ALCOHOL.

Professor J. L. Smith informs us that alcohol of 98 per cent. can be obtained by shaking up the strongest commercial alcohol with freshly burned lime in a tightly closed ves sel, renewing the operation every day for a week or ten days, when the bottles are allowed to remain at rest for a few days for the hydrate of lime to settle, and the original alcohol can be drawn off, free from lime, and of 98 per cent. To obtain absolute alcohol the last draft is to be put into a convenient flask, with the addition of lime in coarse powder and an inverted Liebig condenser attached, so that the alcohol will run back into the flask when condensed. This is then distilled over, and will mark 100 per cent.-1 A, November 20, 1874, 235.

FILLING HOLLOW BRASS ARTICLES WITH MOLTEN IRON.

Atkins, of Birmingham, casts molten iron in hollow brass. objects, without danger of melting them, by simply immersing them in water, which prevents their temperature from rising above 212°. To make weights in this way the brass shell is imbedded in iron filings instead of water. -13 C, November 1, 1874, 1364.

CEMENT FOR MARBLE AND ALABASTER.

It is said that the point of fracture of articles cemented with the following mixture is difficult to find, and that the

cemented place is much stronger than the material itself: Form a thick paste with water-glass (silicate of soda) by adding as much as may be necessary of a mixture of 12 parts of Portland cement, 6 of slaked lime, 6 of fine sand, and 1 of infusorial earth. The article to be cemented need not be heated. It hardens in twenty-four hours.-18 C, December 23, 1874, 815.

CEMENT FOR MARBLE WATER-TANKS.

In the Berlin Polytechnic Society, water-glass with marble-dust, glycerine, and litharge was recommended as a cement for water-tanks of marble slabs, with the statement that it was unaffected by hot water. A mixture of 12 parts of cement, 6 of whitening, 6 of fine sand, and 1 of infusorial earth, stirred to a paste with water-glass, was also mentioned for the same purpose.-34 C, XXIII., 1874, 183.

RENDERING IRON WIRE OF A SILVERY WHITENESS.

To make iron wire of a silvery whiteness it is first treated in a hydrochloric acid bath in which a piece of zinc is suspended. The corroded wire is then brought in contact with a plate of zinc in a bath in which 2 parts of tartaric acid are dissolved in 100 parts of water, with further addition of 3 parts of tin salt (stannous chloride) and 3 parts of soda.

The wire is allowed to remain some two hours in the bath, and is made bright by polishing or by drawing in the drawing-plate. By this galvanized tinning it is quite easy also to whiten wire which is already rolled up spirally, or iron objects of any other form, which gives an advantage over the mechanical method by which the wire is tinned at a high temperature, and then passed through the drawing-plate.21 A, July, 672.

VULCANIZING OF CAOUTCHOUC AT COMMON TEMPERATURES.

The following process devised by Gaulthier de Caulbry is claimed to effect this object. If an intimate mixture is made of flour of sulphur and dry chloride of lime, a decided odor of chloride of sulphur will shortly be noticeable, while simultaneously the temperature of the mixture is appreciably elevated, and the mass becomes plastic by the softening of the sulphur. If a mixture of this kind, in which the sulphur is