slightly inclined, and at about three-fourths of its length, a reservoir was placed. Beyond this the gas passed through copper tubes which were immersed in a freezing mixture. Upon the main tube was a safety valve which allowed the pressure to be regulated at pleasure; this was maintained at about 140 pounds to the square inch. In the first experiment, 538 liters of gas were passed through the apparatus, in the second 467 liters, and in the third 1274 liters. In both reservoirs, 84 c. c. of liquid was obtained in the first experiment, 77 c. c. in the second, and 195 c. c. in the third. Of the 77 c. c., 54 c. c. of sp. gr. 690 condensed in the first reservoir (i. e., by pressure alone without cold) and 23 c. c. in the second, of sp. gr. 650. Of the 195 c. c., 114 c. c. of sp. gr. 691 condensed at +16°, and 81 c. c., of sp. gr. 658, condensed at -18°. As a mean therefore each liter of gas yielded about 158 c. c. of liquid of sp. gr. 680; which is equivalent to one gallon for each 1000 feet of gas. After this treatment the gas was found to have lost its illuminating power, giving no more light when burned from a bat wing jet than does a Bunsen burner. From this and other facts, the author concluded that ethylene is absent from shale gas. Common coal gas when subjected to this treatment gave no appreciable quantity of liquid. The shale products, by weight, therefore, which are obtained on distillation, are:non-luminous combustible gas 20.9 per cent; volatile liquids, sp. gr. 680 dissolved as vapors in the gas 49 per cent; commercial paraffins, sp. gr. 700-800, 52.3 per cent; tarry acid or basic bodies 21.9 per cent. The author proposes a method for commercially preparing these light oils from the gas.-J. Chem. Soc., II, xiii, 856, Sept., 1875.

G. F. B.

3. On the Medico-legal determination of Arsenic.-Having occasion to revise, for purposes of physiological investigation, the methods ordinarily employed for the detection of arsenic in the tissues,* GAUTIER ascertained that they were seriously deficient in quantitative exactness. He thereupon devised an improved method of separating the arsenic from the organic matter, based upon those of Orfila and Filhol, and a modification of the method of Marsh, by which the arsenic is obtained in a weighable form. The former is as follows:-100 grams of the finely divided animal matter is placed in a porcelain capsule with 30 grams pure nitric acid, and moderately heated. At first the mass liquefies, then it thickens and becomes orange-colored. The capsule is taken from the fire and 5 grams pure sulphuric acid are added. Heat is again applied till white fumes appear. Then 10 or 12 grams of nitric acid is allowed to flow drop by drop on the residue, and it is heated to carbonization. An easily pulverizable mass is thus obtained, which is exhausted with boiling water, filtered, the filtrate reduced with a few drops of hydro-sodium sulphite, and precipitated as usual, by a current of hydrogen sulphide. The arsenous sulphide, transformed into arsenic oxide by nitric acid, is ready for the Marsh apparatus. This consists of a * See this Journal for December, 1875, page 474.

flask of 180 to 200 c. c. capacity, having two tubulures, and placed in a vessel of cold water. In it are placed 25 grams of pure zine, on which is poured sulphuric acid diluted with five parts of water. The disengaged gas passes through cotton and then through a tared glass tube heated to redness by charcoal for a length of 20 to 25 cm. The air being expelled, the arsenic, mixed with more dilute sulphuric acid is poured into the apparatus in small portions, an hour being required for the introduction of 5 milligrams of arsenous oxide. The action is kept up for two hours longer, by which time all the arsenic has been carried over. Copper sulphate hinders, platinum chloride facilitates the separation of the arsenic from the solution. After the evolution of gas ceases, the tube containing the annulus of arsenic is weighed again and the amount of arsenic determined. The results are very accurate. In two experiments, in which 5 milligrams arsenous oxide were mixed with 100 grams muscular tissue, the rings weighed 3.72 and 3.67 milligrams respectively; the theoretical quantity being 3.79 milligrams. In a third, 24 milligrams arsenous oxide were mixed with 100 grams blood; the annulus weighed 1-78 milligrams, the calculated weight being 1.88 milligrams. In 2-1 grams of the brain of a rabbit, fed for 15 days with doses of arsenous oxide gradually increasing from 5 to 50 milligrams, the arsenic recovered was sufficient to give a brilliant ring nearly a centimeter long. A vigorous dog was fed with gradually increasing doses of arsenous oxide, from 4 to 80 milligrams, for a month. 100 grams of the liver yielded 5.3 milligrams, and 100 grams of muscle yielded 0-27 milligram of metallic arsenic.-Bull. Soc. Ch., II, xxiv, 250, Oct., 1875.

G. F. B.

4. Formation of Nitrites by Bacteria. - The presence of nitrites in spring waters, which has usually been ascribed to the oxidation of ammonia therein, is now stated by MEUSEL to be produced by the reduction of nitrates by the agency of bacteria. In proof of this, he shows: that such water which contained bacteria and nitrates, but neither ammonia nor nitrites, gave, after standing four days, the reactions of nitrous acid; that antiseptics such as salicylic acid, phenol, benzoic acid, alum, and much salt even, prevent or hinder the production of nitrites; that aqueduct-water containing pure nitrates, which alone does not show the production of nitrites even in presence of bacteria, has this change effected upon the addition of glucose, gum, dextrin, cellulose, starch, etc., in the course of from 2 to 14 days; that freshly distilled water, boiled with glucose and niter, shows no nitrites even after standing for weeks, because bacteria are absent and that putrefying albuminates reduce nitrates to nitrites. The decomposition of cellulose by bacteria in presence of nitrates proves that niter is not only direct food for plants, but that it also performs by its oxygen an important function in the soil. The author believes that these facts have important bearings in agriculture and in medicine.-Ber. Berl. Chem. Ges., viii, 1214, Oct., 1875.

G. F. B.

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5. On the supposed new Hydrocarbon, CH,.-A short time ago PINNER described a new hydrocarbon obtained by the action of sodium upon dichlorallylene, to which he assigned the formula CH2. Further investigation has shown him that the formula is more probably CH, and that the body in question is either allylene itself or an isomer of it. Assuming dichlorallylene to be CH2Cl2, the action of a molecule of sodium upon one molecule of it would be C ̧H2Cl2+Na,=(NaCl)2+C ̧H; but if C,H is produced, two stages of the reaction are required; C, H, Cl2+ (Na)=(NaCl),+CH,Na, and C ̧H, Na2+(H2O)=(NaOH), +C3H4. In the former case the resulting aqueous solution must contain chlorine and sodium in atomic proportions; in the latter, the sodium is double the chlorine. While more alkali than chlorine was always found, it was far from being twice the quantity. To solve the problem, therefore, the author analyzed carefully the tribromide. While CHBr, requires 130 per cent C and 0.4 per cent H, C,H,Br, requires 12.9 per cent C and 1.1 per cent H. In two analyses the carbon was 13.02 and 12.91, and the hydrogen 1.15 and 1.17 per cent. These results, which contradict the former ones, led the author to examine more carefully the composition of dichlorallylene. He finds that instead of its being C, H2Cl2 as assumed, it is really C,HCl, having 3.6 per cent hydrogen instead of 1.83 which the first formula requires. This fact harmonizes both the above observations and settles the new hydrocarbon as CH4. Hence the product of the action of chlorine upon aldehyde is not crotonyl chloral, but butyl chloral; though from it, however, crotonic acid has been obtained by Sarnow. This problem, Pinner is now occupied in solving.--Ber. Berl. Chem. Ges., viii, 1282, Nov., 1875.

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G. F. B.

6. On Aromatic Compounds containing Arsenic.-MICHAELIS has published a preliminary note upon phenyl-arsenous chloride, ASCI,CH,, which he obtained by the action of arsenous chloride upon mercury-diphenyl, in a sealed tube at 170°. The reaction is given as follows:

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Hg(CH)2+(AsC13)2=HgCl2 + (AsCl¿C ̧H ̧)2.

It is a heavy, colorless, strongly refractive liquid, slowly decomposed by water. Investigations upon this and other analogous metallic derivatives are in progress.-Ber. Berl. Chem. Gęs., viii, 1316, Nov., 1875.

G. F. B.

7. On Diacetone-alcohol.-HEINTZ, who has been recently investigating the amines derived from acetone by the action of ammonia, has examined diacetonamine, to see whether the reaction. with its nitrite would result, as is general with other amines, in the production of an alcohol; the nitrogen of both being eliminated as gas, and hydroxyl taking the place of amidogen. Diacetonamine oxalate was dissolved in three times its weight of hot water, and cooled to 5°. To the liquid kept constantly stirred, potassium nitrite was gradually added, in amount equal to * Abstract in this Journal, III, x, 293, October, 1875.

nearly twice the weight of the oxalate. After standing several days, the temperature being allowed slowly to reach that of the atmosphere, the liquid was distilled, whereby some mesityl oxide passed over. The residue, freed from an oily layer by a separating funnel, was neutralized with potassium carbonate and agitated with ether. The etherial solution, dried by calcium chloride, left on distilling off the ether, a liquid boiling between 163.5° and 164.5°, having the formula, CH1202. Its vapor density was 4-19. This is diacetone-alcohol, and it has the rational formula CH

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CH2. CO. CH2-C-.-OH.-Liebig's Annalen, clxxviii, 342, Oct., CH,

1875.

G. F. B.

8. A new relation between Electricity and Light.-Mr. JOHN KERR has succeeded in showing that dielectrified media are birefringent. Two holes were drilled in a block of plate glass so as to leave a space of only about a tenth of an inch between their ends. Copper wires covered with rubber and shellac were inserted into these holes, and the current from an induction coil capable of giving a spark of 20 to 25 cms. passed through them. A second passage is opened to the current of variable length through the air, so that when the spark passes the glass is subjected to an electric strain. The light of a lamp is passed through a Nicol prism, then through the glass, and finally through a second Nicol at right angles to the first. Since every plate of glass exerts a depolarizing action a certain amount of light is transmitted. This is cut off by interposing a second piece of the same plate of glass and slightly turning one of the Nicols. If the plane of polarization is inclined 45° to the line along which the electric action is exerted through the glass on closing the primary circuit, light will be visible in about two seconds. It brightens continuously for nearly half a minute, and if the current is broken, will gradually fade away. The light thus restored cannot be extinguished by any rotation of the analyzer. If the plane of polarization is parallel or perpendicular to the lines of electric force no action is obtained. There is as great an effect with a rapid succession of contrary electrizations as with a continued electrization in one direction.

A small square of glass held edgewise in a vice was then introduced in the path of the beam and compressed feebly horizontally. A second plate like a microscope slide was also inserted and bent by the hands until the light introduced by the depolarization of the first plate was extinguished. From this arrangement of the apparatus, it appears that the dielectrization of the plate glass is equivalent optically to a compression of the glass along the lines of electric force. Dielectrified glass acts upon transmitted light as a negative uniaxial crystal with its axis parallel to the lines of force. Half a dozen other solids were tried, but only two, resin and quartz, gave results worth mentioning. The great difficulty was to get a sufficiently strong superficial insulation, the masses being

too small. A plate of resin was employed of nearly the same size as the glass. Small squares of thin plate glass were placed in optical contact with its two faces and parallel to each other. It gave evidence of irregular strain near the terminals, separated the red and blue rays by a small angle, and was imperfectly transparent. But its chief defect was that it allowed a spark discharge over its surface a length of 7 inches before the distance of the spark terminals much exceeds 2.5 inches. With all these deficiencies, however, it gave a regular and definite effect, and the action was contrary to that of glass.

A plate of quartz cut perpendicular to the axis, 3 mms. thick and 20 long, was employed with a result similar to that of glass.Phil. Mag., 1, 337.

E. C. P.

9. Waves on Mercury.-M. C. DECHARME states that by blowing through a tube touching the surface of mercury, we may produce a sound and circular waves forming a symmetrical network upon the liquid. The smaller the interior diameter of the tube, the higher and weaker is the sound and the shorter the waves. As long as the diameter is less than about half a millimeter, the sound resembles the buzzing of an insect. When the diameter amounts to 7 or 8 mms. the sound assumes a clear and distinct musical character. With larger tubes the note becomes loud. There is a great tendency of the sounds to pass to their harmonics, with slight changes of the pressure of the air or of the length of the immersed portion of the tube, especially when the latter has a diameter of 2 to 5 mms. For this reason it is difficult to obtain single sounds, but they are almost always high and unstable harmonies. The best results are attained with tubes 0.8 to 5 mms. in diameter, held vertically so as just to touch the surface, and cut off perpendicular to their axes. The tube is then connected with a large rubber vessel full of air and compressed by a weight which should be greater the smaller the tube.

In general the sounds thus produced depend, as regards their height, quality and intensity, on the diameter, length and nature of the tube, the thickness of its edges, the form of the edges of the orifice, and on the temperature, pressure and nature of the gas; finally and above all, on the capacity of the reservoir of air, or rather on the harmonic ratio of its volume to that of the sounding tube and of the connecting tube. This last condition is so essential that a tube giving good results with one reservoir will not work satisfactorily with another. An important application of this device is to the production and projection of interference waves in an elliptical vessel. The nodes and loops are in this case clearly marked, fixed and symmetrical. The concord of the third, fifth and octave may be similarly projected on a screen with great clearness by employing two sounding tubes.--Journ. de Phys., iv, 207.

E. C. P.

10. Spectrum of the light of the blue Grotto of Capri.-Dr. H. W. VOGEL, on a recent visit to Capri, tested the light of the blue grotto with a spectroscope. As the entrance is only about four