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anides. The bulk is augmented proportionably to the weight. The same writer points out very clearly the evils attending this excessive adulteration. The chemical and physical properties of the silk thus treated are materially modified. What is sold as silk is, in reality, a mere agglomeration of heterogeneous matters devoid of cohesion, held together temporarily by a small portion of silk. The strength and elasticity of the fibre are likewise reduced. From being in its natural state one of the most stable of substances, and but slightly combustible, in its adulterated state it burns like tinder if touched by a flame. It is likewise affirmed to be liable to undergo spontaneous decomposition, and to absorb gases with the evolution of heat which sometimes leads to actual combustion. The adulterated silk when burning scarcely gives off the characteristic odor of animal matter.

It is of interest to supplement our notices in last year's Record of the artificial production of vanillin-the active principle of the vanilla bean (which is now a commercial operation)-by reference to a suggestion for obtaining it largely by another process. In several manufacturing operations pine-wood is treated in iron boilers, under high pressure, with a solution of caustic alkali. The resulting liquid contains various salts of soda, and, if the temperature has not been too great, among them the soda salt of vanillin. Experiments made with the view of establishing this fact are conclusive, its presence being demonstrated by the presence of an intense vanilla odor, which becomes more prominent when the liquid is treated with an acid and left standing for several days. It has thus far, however, been found impossible to extract the crystallized vanillin from the above-named liquid, though in all likelihood this consummation will not be long delayed.

M. Gerard gives the name of Apparatine to a colorless, transparent substance which he obtains by heating starch, or substances rich in starch, with caustic alkali. The product resulting from this treatment is said to be excellently adapted as a dressing for all kinds of textile fabrics-cotton, woolen, or silk-to which it imparts a velvety gloss impossible to obtain by any other mode of treatment.

M. Paulet's observations upon the chemical operations in

volved in the preservation of timber, contribute materially toward the rational explanation of conflicting and often contradictory results obtained in practice. This author's investigations lately placed before the French Academy--were devoted specially to the examination of the destructive action which takes place in wooden railway sleepers injected with sulphate of copper. It is generally held that the protective action of metallic salts is due to their combination with the ligneous tissue, and especially with the nitrogenous matter, which is rendered insoluble and poisonous to living beings. This operation the author claims to be insufficient. He affirms, from his studies of the action of metallic salts, and especially of sulphate of copper, upon the nitrogenous matter of wood, that the albumino-cupric precipitate is not absolutely insoluble in water, and that it is especially soluble in water containing carbonic acid. The nitrogenized matter in wood is partly soluble and partly insoluble. The soluble albuminous portion is fixed by the metallic salt, which combines also with the insoluble nitrogenous matter. The water, especially if charged with carbonic acid, destroys and removes this metallic compound; in proof of which the author gives a number of examples, which show that the copper gradually passes out of the combination and disappears altogether, giving place to the carbonate of lime. The process is explained to be as follows: The carbonate of lime contained in the ballast is slowly dissolved under the influence of the rain-water, and penetrates gradually into the wood, substituting the copper. So long as the copper remains in its original combination, its preservative action continues. The carbonate of lime is not a septic agent, but it eliminates the preservative body from its compounds, and restores the matter to be preserved, if not to its natural state, at least to one which facilitates the access and the action of destructive agents. This theory is confirmatory and explanatory of the fact, long established by observation, that railway sleepers, etc., are destroyed most rapidly in calcareous soils; and the affirmation of the imperfect insolubility of the albumino-metallic precipitate, is additionally confirmed by the fact that the injection of timbers with metallic compounds has been found to afford but little protection to the same where they are immersed in fresh or salt water.

Some further comments on the methods of injecting timber with preservative compounds will be found under the department of General Technology.

It is of importance to record that Coupier's process for producing aniline colors without the employment of arsenic is being largely introduced. It appears that Coupier some time ago succeeded in producing fuchsine by the action, at a suitable temperature, of hydrochloric acid and iron in small quantities on pure aniline and nitrotoluol. Although it was demonstrated that the aniline red obtained by this method was identical with that usually manufactured, and that the yield was greater than where arsenic acid was used, the process was until lately very sparingly introduced on the commercial scale. Recently, however, we learn, the Gesellschaft für Anilin Fubrikation of Berlin has erected new works, where no arsenic acid is used in the preparation of colors. Not only fuchsine, but all the colors derived from it, are made, and all are warranted to be free from this poisonous agent. The company is producing from 200 to 300 kilogs. per diem, and the product is affirmed to be not only purer, but stronger than that made from arsenic acid. Being entirely free from this poisonous substance, these dyes are suitable for a great variety of industrial uses where the others have been found to be dangerous. Upon this subject the Chemical News expresses the hope that, the commercial success of the innovation being demonstrated, other manufacturers of these dyes will adopt the new method, and relinquish the old arsenic-acid process, which, apart from the inconveniences it has caused both manufacturers and consumers, has led to many lamentable accidents.

Eosin (from wc, dawn) is the name by which a newly introduced dye-stuff has been designated. In its solutions and upon silk it is characterized by exhibiting a gorgeous fluorescence, in which the beautiful tints of rose and garnet red predominate. It is brought into commerce in the form of a brown red powder, with a greenish, metallic sheen. It is soluble in water and in alcohol.

Delachanal and Mermet have devised a lamp for photographic purposes which effects the continuous combustion of carbon-disulphide and nitrous oxide. Riche and Bardy have investigated the photo-chemical intensity of various flames,

and give the following tabulation as the correct expression of the relative value of several lights examined, in which the intensity increases with the figures:

Drummond-light......

Zinc burning in oxygen..

Magnesium lamp..

Relative Chemical
Energy.

3

4

5

6

Flame produced by leading nitrous oxide into that of carbon

6-7

Flame produced similarly by oxygen.......

Oxygen directed upon the flame of burning sulphur.

8

Flame of nitrous oxide and carbon-disulphide vapor.....

disulphide burning in an open dish......................

From the foregoing it appears that the light produced by the combustion of sulphur in oxygen is possessed of extraordinary chemical energy, and may be applied to photographic uses with excellent effect.

Stein, in a communication upon the subject of normal weights and measures of rock-crystal, remarks that Kekulé pointed out, some time ago, the fact that all amorphous bodies, whether produced by casting, rolling, hammering, or stamping, are possessed of the tendency to go over into the crystalline condition. The molecules of such substances. he regards as being in abnormal positions relative to each other, and the striving toward crystallization is the natural effort to assume the position of equilibrium. For these reasons, Kekulé objected to normal weights and measures made of metal, affirming that they could not be relied upon to remain constant; while, on the contrary, this objection would not hold good of such normals when constructed of a crystallized substance, as, for example, of rock-crystal. Recognizing the validity of the foregoing arguments, the author has had such weights and measures cut at Oberstein. To produce the measures, the pieces are cut exactly parallel with the optical axis of the rock-crystal, so that the main axis of the crystal coincides with the median line of the rod. The same rule is likewise observed with the weights, by which an unequal expansion is avoided. These normal weights and measures are manufactured at Oberstein by H. Stern, who has likewise devised a method of attaching the pieces to each other, when measures of considerable length are required, in such a manner that any alteration of the

scale of parts is not possible, and the correctness of the division, as also of the total length, may be under control. For these weights and measures a number of advantages are claimed. The considerable hardness of the rock-crystal (7) protects the weights from abrasion by usage, to which objection all weights of metal are open. The rock-crystal is even more indifferent to the action of acids and alkalies than platinum, while it is utterly indifferent to oxidation, to which weights of metal are more or less liable. Moisture has no effect upon it, since it is not hygroscopic. Rock-crystal, as compared with the metals, has a very small co-efficient of expansion, on which account the errors arising from variations of thermometer and barometer are reduced to a minimum. The weights are not objectionable on the score of expense, their cost being quite moderate. As produced by Stern, the larger weights, from 50 grammes to 1 gramme. inclusive, are made of rock-crystal, the pieces having the same form as the commonly used weights of gilded brass, while the weights under 1 gramme are made as usual of platinum. Fresenius, who has examined and employed them, declares them to be admirably adapted for analytical work.

Lewin impregnates sandstones with a solution of sulphate of alumina, which he follows with water-glass. The stones thus impregnated may be polished and appear like marble. They resist the action of fire and of the atmosphere, and are well adapted both in appearance and durability to take the place of marbles. By preparing them at a high temperature the stones take on a species of glaze, which may be decorated with a variety of colors to imitate colored marbles and the like.

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