paraffin will effectually preserve it from deterioration by the action of the weather. The paraffin, it is said, hardens the plaster so much that the finger-nail will scarcely scratch it, increases its weight considerably, gives it an appearance of transparency like ivory, and preserves it though subjected to repeated washings. The process of saturation is stated to be similar to that employed in the saturation of plaster casts in stearin.

IMPROVEMENT IN PLASTER OF PARIS.

A new process of manufacturing plaster of Paris is an nounced, which is said to afford excellent casts, that set slowly, and are of a pure white color. The process consists briefly in immersing the unburnt gypsum for fifteen minutes in water containing ten per cent. of sulphuric acid, after which it is calcined.

WATER-PROOF DRESSING FOR LEATHER.

A dressing for rendering leather water-proof, made as follows, as proposed by Hager, has been found to answer the purpose: Soften one part of India rubber in five parts of illuminating petroleum, by digestion for a day, and add twenty parts of paraffin to the pasty mass, and digest again for half a day, with repeated stirring, and then mix it with five parts of oil and five of tallow, and finally add ten of petroleum, or enough to give the mass the consistency of butter.-8 C, February 11, 1875, 55.

EFFECT OF FREEZING UPON THE COLOR OF FABRICS.

The reduction of the color of indigo blue on cotton by freezing, noticed by Köchlin, is ascribed by Goppelsröder to ozone in the air, which, he found by experiments, acts at temperatures below the freezing-point, if the material is not dry. He found that cochineal red on wool was decidedly weakened, but not bleached, after a week's exposure to ozone; aniline black remained unchanged; aniline brown on cotton became yellowish-orange; fuchsin, aniline blue and violet, corallin, and iodine green were bleached, as well as dyewood lakes, and even Turkey red. Ozone is also very effective in developing certain colors. This action is very

decided in the case of aniline black, which is developed by

it in from one to one and a half hours. The Gramme machine is suggested for the production of ozone.—24 C, XV.,

113.

WATER-PROOFING FABRICS WITH BICHROMATED GELATIN,

In cases where a certain degree of stiffness is not objectionable, as in the manufacture of canvas trunks, knapsacks, etc., and possibly also of roofing-paper, the material may be easily and cheaply rendered water-proof by simply stretching it in a frame, and coating it several times with a hot five to ten per cent. solution of gelatin, to which one part of bichromate of potash has been added in solution for every five of gelatin, and then exposing it to sunlight, or diffused daylight.-13 C, December 15, 1875, 1560.

DYEING PARCHMENT PAPER WITH ANILINE COLORS.

So-called vegetable parchment can, like silk and wool, be combined directly with aniline dye-stuffs without a mordant, and in this way a very durable material, of a variety of colors, may be prepared, suitable for book-bindings, fancy boxes, cases, etc.-5 C, XXXII., 1875, 256.

DISCHARGING ANILINE BLACK FROM FABRICS.

In order to discharge black from fabrics dyed with aniline black, Witz treats the portion with an acidified solution of permanganate of potash, whereby peroxide of manganese is precipitated in the fibres. A solution of oxalic acid is then used, which removes the peroxide, and leaves the parts of the cloth acted on perfectly white. It is suggested that a solution of the permanganate, thickened with infusorial earth, could be printed on fabrics, and thus discharge white figures on an aniline-black ground.-6 C, January 21, 1875, 29.

ARTIFICIAL ULTRAMARINE INDUSTRY.

The total production of artificial ultramarine during the year 1874 was 150,000 cwt., of the value of $3,000,000. The manufacture is chiefly confined to Germany and France, the former country exporting annually about 60,000 cwt. In addition to the greenish-blue, pure blue, and violet-blue shades, a violet ultramarine was among the exhibits of the Vienna Exposition. The composition and mode of prepara

tion of this new product are as yet unknown.-Manuf. Review, VIII., 18.

PROHIBITION OF ARTIFICIAL ALIZARINE IN RUSSIA.

By a recently issued Imperial Ukase, the importation of artificial alizarine into the Russian Empire is prohibited. The purpose of this prohibition is said to be the protection of the cultivators of the Russian madder (marena), who for the last twenty years have been extensively engaged in its culture in the province of Daghestan. A few years ago the value of the crop was estimated to have an annual value of three millions of rubles, but it has now greatly fallen off. The aniline colors are, curiously enough, included under the prohibition-with the single exception of crystallized magenta-which is the one most extensively contaminated with arsenic.-Manuf. Review, VIII., 18.

GOLDEN-OLIVE ON CLOTH.

For two pieces of cloth-sixty-one pounds-dissolve four pounds of alum and two pounds of purified argol in a decoction of thirty pounds of fustic; add four pounds of turmeric and two pounds of orchil, turn the fabric in, boil for an hour, and then bring to the desired shade with sulphate of indigo, and further boiling.-23 C, August 27, 1875, 631.

DYEING SILK.

The following processes are recommended by Reimann's Fürber-Zeitung for dyeing silk. First remove the gum, except from tram, best by moving the silk about, suspended on sticks, in a bath heated to boiling, containing one quarter a pound of soap for each pound of silk; allow it to remain in this for twenty minutes, and repeat the operation in a bath containing one fifth of a pound of soap for each pound of silk. Tram must retain its gum, in order that the fabrics made with it may have the necessary stiffness and body; to prepare it for dyeing, place it, until its yellow color disappears, in a bath, at a temperature of 212°, prepared by mix ing equal parts of sulphuric, hydrochloric, and nitric acids, and adding water enough to bring it up to 30° Baumé. For light shades then wash and bleach it; for dark shades the bleaching is unnecessary. Treat subsequently in the

same manner as ungummed silk. In dyeing brown, place the silk, before ungumming it, in a tin composition of 32° Baumé, rinse it, on removal from this, three times, ungum it, and dye in a fresh bath of alum, indigo carmine, fustic, and logwood, according to the shade desired.-24 C, XXXIII., 1875, 260.

BEAUTIFUL BLACK FOR STRAW HATS, ETC.

On

The following process, which is said to afford a beautiful and durable black on straw hats, can be readily applied, if desired, with but little trouble or loss of time by cloth dyers: The hats are first placed for several hours in a moderately strong soda or lye bath, and, after rinsing from it, are steeped overnight in an old sumac or gall bath. removal from this, they are allowed to drain off well, and placed for two or three hours in a pyrolignate of iron bath. They are then exposed to the air for some time, when they almost blacken, and rinsed, and dyed up lukewarm with logwood, and drawn through a weak solution of glue, and dried and brushed.-5 C, XXXIX., 1875, 312.

DYEING BLACK WITH CERIUM SALTS.

Professor Böttger calls the attention of the Physical Society of Frankfort to the recent introduction of the bisulphate of cerium in dyeing, especially to the production with it, in connection with chloride of aniline, of an intense deep black on cotton yarns and fabrics. He found that by dipping the yarn several times, alternately, in a solution of chloride of aniline, slightly acidified with hydrochloric acid, and in a solution of bisulphate of cerium, and finally in a solution of bichromate of potash, it acquired a remarkably beautiful black color.-5 C, XXXVII., 1875, 295.

NEW BLACK FOR WOOL.

Wool dyed black according to the following recipe, it is said, does not rub off in the least, while the fibres remain loose and open, and it has a desirable reddish cast. Boil the thoroughly washed wool well for an hour and a half in a bath composed, for one hundred pounds of wool, of two and a half pounds of chromate of potash, two and a half pounds of alum, one half pound of blue vitriol, and two pounds of

commercial sulphuric acid, and dye it, without rinsing in fresh water, with twenty pounds of logwood and twenty pounds of Brazil-wood. It is advantageous for the color to allow the wool to remain in the mordant for twelve hours.5 C, XXXII., 1875, 256.

XYLINDEIN, A NEW DYE-STUFF.

The name xylindein has been given to a green dye-stuff, examined by Fordos and Rommier, which results as a pathological effect of Peziza æruginosa in dyeing wood of the beech, oak, and birch, often to such an extent as to impart a dark blue-green appearance to large blocks. This coloring matter has been extracted from the green-colored wood, by Liebermann, with carbolic acid, and has been precipitated from the dark-green solution in dark-green flakes, by the addition of alcohol or ether. By recrystallization from the solution in carbolic acid it was obtained in small four-sided crystals, of a high coppery lustre. These are insoluble in most solvents, except in concentrated sulphuric acid, with a grass-green color, and in carbolic acid and aniline, with a beautiful dark-green color. No formula can as yet given for it.-1 C, IV., 1875, 64.

EOSIN, A NEW FLUORESCENT DYE-STUFF.

be

A new dye-stuff has been introduced into the market under the name of eosin, by a German company. It is charac terized, in solution or upon silk, by a beautiful fluorescence, combining in a most decided manner beautiful rose and reddish-brown tints. It consists of glistening greenish scales, readily soluble in water, and of an alkaline compound of a yellow dye-stuff, precipitable by acids. It seems related to the Bavarian phthalic acid dye-stuffs. Meister, of Zurich, employs it instead of litmus in the rapid titration of alkalies, since the disappearance of its beautiful rose color, upon acidification, is much more marked and sudden than the change of the blue of litmus.-8 C, January 7, 1875, 11.

A NEW ANILINE RED.

Dr. Isidor Walz has called attention to the discovery of a new coal-tar color which promises to become of importance. It yields shades exactly like those of cochineal, and almost