additional burners. To avoid the glare, the light was inclosed in a globe of ground glass.-Revue Industrielle, VII., May, 1876, 169. MAGNETISM OF COBALT AND NICKEL It has long been known that a bar of iron when magnetized becomes appreciably elongated. Barrett has recently sought to discover whether cobalt and nickel are similarly affected. With cobalt, a slight lengthening may be perceived; but in the case of nickel a contraction, about equal to the expansion of iron, takes place. The bar of nickel used was about two feet long.-1 A, June 30. D. CHEMISTRY AND METALLURGY. CHEMICAL ACTION OF SOLAR RAYS. Henry E. Roscoe states that although his method of measuring the varying intensity of the chemically active rays as affecting chloride of silver paper has been the means of pointing out many important facts, yet it has not been introduced as a regular portion of the work of meteorological observatories; until which is done we can not hope to obtain any thing like a complete knowledge of the laws of distribution of the chemical rays over the earth's sur face. This neglect of Roscoe's method is, in part at least, due to the labor of observing. He has, therefore, advised a modification of the instrument described by him in 1865, and as thus modified the constant sensitive paper is exposed to the action of total daylight at given intervals, say at every hour during the day, by a self-acting arrangement for accurately noting the times. These hourly records are then read off in the evening by the observer. Many mechanical. difficulties have been overcome through the skill of Mr. Jordan, of Manchester, and the instruments, as described by Roscoe in the last volume of the "Transactions of the Royal Society of London," are said to give complete satisfaction. In order to read off the intensities of recorded photographic images, a standard series of graduated tints is provided. Special directions are given for the preparation of the sensitive paper. The correction due to the reflection and absorption of the glass cover is also investigated; and the comparison of observations made by hand, and by the self-recording instrument, over twenty days with the two methods, closely agree.-Philosophical Transactions, London, 1875, 655. OCCLUDED HYDROGEN IN SO-CALLED EXPLOSIVE ANTIMONY. The presence of a considerable amount of chloride of antimony was demonstrated several years ago, by Professor Böttger, in the so-called explosive antimony formed on the negative pole, consisting of fine platinum wires, the positive one being of massive antimony, when the current of a single additional burners. To avoid the glare, the light was inclosed in a globe of ground glass.—Revue Industrielle, VII., May, 1876, 169. MAGNETISM OF COBALT AND NICKEL. It has long been known that a bar of iron when magnetized becomes appreciably elongated. Barrett has recently sought to discover whether cobalt and nickel are similarly affected. With cobalt, a slight lengthening may be perceived; but in the case of nickel a contraction, about equal to the expansion of iron, takes place. The bar of nickel used was about two feet long.-1 A, June 30. D. CHEMISTRY AND METALLURGY. CHEMICAL ACTION OF SOLAR RAYS. Henry E. Roscoe states that although his method of measuring the varying intensity of the chemically active rays as affecting chloride of silver paper has been the means of pointing out many important facts, yet it has not been introduced as a regular portion of the work of meteorological observatories; until which is done we can not hope to obtain any thing like a complete knowledge of the laws of distribution of the chemical rays over the earth's sur face. This neglect of Roscoe's method is, in part at least, due to the labor of observing. He has, therefore, advised a modification of the instrument described by him in 1865, and as thus modified the constant sensitive paper is exposed to the action of total daylight at given intervals, say at every hour during the day, by a self-acting arrangement for accurately noting the times. These hourly records are then read off in the evening by the observer. Many mechanical difficulties have been overcome through the skill of Mr. Jordan, of Manchester, and the instruments, as described by Roscoe in the last volume of the "Transactions of the Royal Society of London," are said to give complete satisfaction. In order to read off the intensities of recorded photographic images, a standard series of graduated tints is provided. Special directions are given for the preparation of the sensitive paper. The correction due to the reflection and absorption of the glass cover is also investigated; and the compar ison of observations made by hand, and by the self-recording instrument, over twenty days with the two methods, closely agree.-Philosophical Transactions, London, 1875, 655. OCCLUDED HYDROGEN IN SO-CALLED EXPLOSIVE ANTIMONY. The presence of a considerable amount of chloride of antimony was demonstrated several years ago, by Professor Böttger, in the so-called explosive antimony formed on the negative pole, consisting of fine platinum wires, the positive one being of massive antimony, when the current of a single Bunsen element is passed, for three or four days, through officinal solution of terchloride of antimony, with a resistance of about eight hundred feet of copper wire in the circuit. He has recently also detected occluded hydrogen in it, possessing identical reducing properties with the hydrogen absorbed by palladium. Thus, if the platinum wires, covered with recently deposited explosive antimony, are placed in a very dilute aqueous solution of ferricyanide of potassium, the partial conversion of the latter into ferrocyanide will be evident in the course of ten or fifteen minutes. Pure antimony, perfectly free from arsenic, will not produce such a result. Since the liquid employed is a hydrochloric-acid solution, the liberation of gaseous hydrogen at the negative pole, with the antimony, by decomposition of the acid, might be expected, but not the slightest trace of it could be detected, while, on the other hand, the presence of chlorine at the negative pole, in combination with antimony, without the evolution of hydrogen, is so remarkable that it seems desirable to test other metallic chlorides thus electrolytically.-15 C, XXII., 1875, 337. AMERICAN BROMINE. The increased demand for bromine, after the introduction of potassic bromide into medicine in 1866, led to its preparation from the mother liquor at the different salt-works of Pennsylvania, and subsequently at those of Ohio and West Virginia. The method employed is the usual one with binoxide of manganese and sulphuric acid. From 1867 to 1870 the production increased from 11,000 pounds to 194,000 pounds. Up to 1870 all was consumed in the United States, but since then it has been exported. The price, however, has been so depressed by excessive production that no new works for its preparation are being established. -18 C, February 9, 1876, 95. DETERMINATION OF OZONE IN THE AIR. The determination of the quantity of ozone in the air has not yet been achieved by any convenient method, since the tint of the ordinary ozone test-papers is determined by the velocity of the wind. It was supposed by Von Pettenkofer that the absence of the ozone reaction in the atmosphere of closed dwelling-rooms was due to the slight circulation in |