trimethylcarbinol. Pseudobutylene, isomeric with the former, suffers a similar change but much more slowly.-Liebig's Ann., clxxx, 245, Feb., 1876. G. F. B. 9. On the Trimethylbenzols of Coal tar Oil and their Separation from each other.-JACOBSEN has examined very carefully the trimethylbenzols obtainable from coal tar and has shown that only two, mesitylene and pseudocumol are present therein, the third one which theory points out as possible, not existing in the oil at all. Pseudocumol forms only a single sulpho-acid with sulphuric acid, the salt supposed formerly by the author to be isocumolsulphate of barium being a well characterized double salt of mesitylene-sulphate and pseudo-cumol-sulphate. The two trimethylbenzols found separated readily by converting them into the amides. of the sulpho-acids, by obtaining first the chlorides by the action of phosphoric chloride and then the amide by the action of ammonia upon this. By crystallization from alcohol, the two substances, mesitylene-sulphamide and pseudocumolsulphamide, are easily and completely separated, the former being far more soluble. On treating the pure amides with hydrochloric acid, the hydrocarbons were regenerated.-Ber. Berl. Chem. Ges., ix, 256, Feb., 1876. G. F. B. 10. On the Detection of Phloroglucin and Nitrites.—When very dilute solutions of phloroglucin and of toluidine or aniline nitrate are mixed and a few drops of a solution of potassium nitrite is added, the liquid, at first clear, becomes turbid and brownish-yellow, then orange, and deposits a cinnabar-red precipitate. WESELSKY, who discovered this reaction, proposes it as a test for phloroglucin and nitrites. One c.c. of a solution, containing 0.0005 gram phloroglucin was mixed with one c.c. of a solution of toluidine nitrate saturated at ordinary temperatures, diluted to 50 c.c. with water and treated with one c.c. of a solution containing 0.001 gram potassium nitrite. In 15 minutes the solution became yellow and in three hours the cinnabar precipitate was obtained. Similar reactions are obtained with aqueous solutions of maclurin and catechin, and decoctions of fustic and hops, in place of phloroglucin.-Ber. Berl. Chem. Ges., ix, 216, Feb., 1876. G. F. B. 11. On the Succinic acid obtained from Active Tartaric acid.— Pasteur announced some time ago the existence of an optically active succinic acid, and Kekulé showed that the succinic acid derived from active malic acid was itself inactive. BREMER and VAN'T HOFF, deeming the existence of such an active succinic acid extremely improbable, since its molecule contains no asymmetrical carbon atom, have examined the acid which is produced along with dextro-malic acid, by the reduction of dextro-tartaric acid. The acid in question proved to be absolutely inactive and to agree in all respects with ordinary succinic acid. Hence we have: (1) Dextro-tartaric acid, CO,H. C(OH). CH(OH). CO2H, containing two asymmetrical carbon atoms and rotating the polarized plane (a)=6°6; (2) Dextro-malic acid, CO2H.CH(OH). CH,. CO2H, containing one asymmetrical carbon atom and rotating (a)=3°3; and (3) Succinic acid CO2H.CH,.CH,. CO2H, containing no asymmetrical carbon atom, and being inactive.-Ber. Berl. Chem. Ges., ix, 215, Feb., 1876. G. F. B. 12. On the Re-conversion of Paroxybenzoic acid into Salicylic acid.-Neutral potassium salicylate, as Ost has shown, when heated to 210°-220°, splits up into potassium paraoxybenzoate, phenol, and carbon dioxide; while the sodium salt affords no paraoxybenzoate. KUPFERBERG has succeeded in effecting the inverse reaction and in converting the paraoxybenzoate again into salicylate. 39.5 grams sodium paraoxybenzoate, heated to 280° to 295° for six hours in a current of carbon dioxide gas, yielded 7 grams of salicylic acid; or 56 per cent of the acid present. Salicylic acid is converted into paraoxybenzoate by heating the neutral potassium salt to 220°; paraoxybenzoic acid is converted into salicylic by heating the sodium salt to 290°.-J. pr. Ch., II, xiii, 103, Feb., 1876. G. F. B. 13. On a new Hydro-oxy-benzoic Acid.-In the hope of obtaining trimesinic acid-an acid containing three carboxyl groupsEMMERLING and OPPENHEIM oxidized oxyuivitinic acid by means of potassium manganate. The product, precipitated by hydrochloric or sulphuric acid, is purified by crystallization from hot water. It appears in thin colorless needles, fusing at 274°5, and giving a yellow precipitate with ferric chloride. Analysis gave it the formula C,H,O,, the barium salt being (C,H,O3)2 Ba, (H2O), and the silver salt C,H,AgO3. Fusion with potash separates water and converts it into benzoic acid. -Ber. Berl. Chem. Ges., ix, 326, March, 1876. G. F. B. 14. On Vicin, a Constituent of Vicia sativa.-Some time ago, RITTHAUSEN described a crystallized highly nitrogenous substance obtained from the seeds of the vetch. He now shows that it is a new body, and has the composition CH,,N,O,. He assigns to it the name vicin. A kilogram of seeds yielded 3-2 grams of vicin.-Ber. Berl. Chem. Ges., ix, 301, March, 1876. 16 3 G. F. B. 14. Acoustic Attractions.-M. DVORAK has examined the attractions and repulsions of small pendulums hung near sonorous bodies. A square of paper or a piece of cork is hung by a silken thread, and held near a wooden rod vibrating slowly. Varying the positions of the pendulum it is sometimes attracted and sometimes repelled. These motions seem to be due to the air-currents approaching or receding from the rod, and the motions of the cork served to determine approximately the directions. These results were verified by the motions of a flame and the indications of a very sensitive water manometer. The air thrust aside by the vibrating rod escapes laterally, repelling light bodies. This is replaced by air forming counter-currents toward the rod, producing the effect of attraction. When the amplitude of the vibrations is small, the rod acts like the prongs of a tuning fork, and attraction takes place in every direction. In front of the opening of a tube of Kundt, is placed a second open tube, giving the same sound as the first, and suspended by two threads. Making the first tube resound loudly, the second tube is strongly repelled. The same effect is obtained if the second tube gives one of the harmonies of the first. Placing two tubes facing each other opposite the tube of Kundt and perpendicular to its axis, they tend to approach each other. With a very sensitive manometer it appears that in a column of air in a state of permanent vibration, the air at the nodes has an excess of pressure. This accounts for the heaping up of water in the loops of a tube of Kundt. It is explained by admitting that the amplitude of the vibrations cannot be neglected compared with their length. It follows that there ought to be a continuous motion of the air from a node to a loop. This might be proved by filling the resonant box of a tuning fork with the fumes of chloride of ammonium and seeing if they are thrown out when the fork is set in vibration. If a bell is filled with water and a drop of oil allowed to fall on it, the circular film becomes quadrangular when the bell is sounded. The water-currents start from the nodes and accumulate at the loops. A disk of glass is attached to the end of a rod vibrating longitudinally. If a glass drop is hung opposite the disk it will be repelled at the center and attracted around the periphery. There are then, as with air, currents outward at the center, and counter currents inward along the edges.-Journ. de Phys., v, 122. E. C. P. 15. Correlation of Forces.-M. GROVE describes a convenient apparatus for showing the relations between heat, electricity, and mechanical force. The arrangement is as follows: Two of Clamond's thermo-electric generators are connected for quantity and put in communication with a gram machine, in such a way as to set this in motion. In the circuit is inserted a sort of electric lamp, in which a platinum wire, placed in the center of a small globe (which protects it from agitation of the air) can be raised to incandescence. The only difficulty of the experiment consists in so regulating the length and diameter of the platinum wire, that it may be raised to a red heat while the thermo-electric current retains sufficient intensity to drive the gram machine. A circuit entirely metallic is thus obtained, with which the following transformations can be effected; (1.) The gram machine being excluded from the circuit, a portion of the heat, transformed into electricity by the thermopile, reappears as heat in the wire. (2.) The wire being excluded from the circuit and the machine introduced, a portion of the heat, transformed into electricity in the pile, reappears as work in the machine. (3.) The wire and machine being included in the circuit, a part of the heat, transformed in the pile into electricity, produces heat in the wire and work in the motor. If we then stop the machine, the incandescence of the wire is increased. The machine being libera ted, on the other hand, starts, and the wire cools as its motion increases. The expenditure of heat needed to develop an increasing quantity of mechanical work is thus rendered sensible to the eye. (4.) Turning the machine in the direction of the rotation produced by the current, a velocity may be reached such that the incandescence shall completely disappear. (5.) Turning the machine in the opposite direction, there is considerable resistance, and the wire rapidly grows hotter, and is soon fused. Thus, in the metallic circuit under consideration, the circulation of a given quantity of energy may appear exteriorly in the form of heat, or, as work. If, by an exterior force, we introduce into the circuit an additional quantity of work, the increase of the quantity of energy put in circulation is rendered visible by the incandescence of the wire; any communication outward from the circuit, of a certain quantity of energy which circulates in it, appears, on the other hand, in diminution, or even disappearance, of the incandescence.-Journ. de Phys., iv, 359; Nature, xiii, 434. E. C. P. 15. Change of Volume of Electric Conductors.-HERR EXNER has measured the change in length of a conductor through which an electric current is passing, by a method free from the error caused by the expansion due to the heat generated by the current. Two pieces of the same wire of nearly equal lengths were hung one over the other, and so connected with a battery that the current might be passed through either. The lower wire passed through a glass which might be filled with water if desired. The elongation was measured by resting the end of the wire on a lever carrying a mirror whose deflection was read by a telescope and scale. The current being passed successively through the two wires a different deflection was obtained in each case, but these were rendered equal by inserting an additional resistance in circuit with that wire whose elongation was greater. The tube was now filled with water so as to carry off the heat generated in the lower wire as rapidly as possible. It was found that the galvanic expansion was only 12 to 22 per cent of the heat expansion and no connection was recognizable with the nature of the metal employed. If it be considered that these values, of course, can only by an upper limit, it will follow from the smallness of the effect obtained that there is no sufficient ground for the hypothesis of a special expansion power of the galvanic current. There can hardly be any doubt that the slight expansion which the waterenclosed wire still shows is simply and alone due to the heat remaining in it.-Nature, xiii, 452. E. C. P. 16. Proper Motion of the Stars.-P. SECCHI points out a new source of error in the measurement of the proper motion of the stars by the displacement of the lines of the spectrum. The author tabulates a number of the observations made by Huggins, Vogel and himself, and those at Greenwich Observatory, and shows there is considerable contradiction in the results. The question arises whether there may not be some systematic error in the manner of observing or in the instruments. Comparing the dark line F of Sirius with the hydrogen line Hp of a Geissler tube, he got always the same resulta shortening of the Sirius line occurs (contrary to Huggins) when the telescope was carried along by the clock-work, and the assistant was at the seeker to keep it on a fixed point corresponding to the slit of the spectroscope; but if the clock-work stopped, or the assistant deranged the position of the star, the light line was displaced and came into coincidence with the star line. Dispensing with clockwork the line was found to be on one side or the other, according as the star was looked at on one side or the other of the axis of the telescope. A change was also noticed on turning the spectroscope 180° on its axis. No attempt is made to explain these phenomena, but they are pointed out as possible sources of illusion. - Comptes Rendus, lxxxiii, 761, 812; Nature, xiii, 480. II. GEOLOGY AND MINERALOGY. E. C. P. 1. Paleozoic fossils from a limestone associated with the Serpentine formation (Zone of the Pietre verdi) of Chaberton (Alpi Cozie).-Prof. B. Gastaldi, in the Bulletin of the R. Comitato Geol. d'Italia for 1875, p. 346, has published a paper on discoveries made by G. Michelotti, a letter from whom is published in the paper. An accompanying geological section, by Michelotti, gives the stratification of the upper part of Mt. Chaberton: No. 1, the dolomitic limestone; 2, anthracitic sandstone of a red color, with black beds containing lamellar hematite, etc.; 3, quartzyte, with beds of gypsum; 4, talcose "calcischist," of a greenish color. Michelotti states that in an amphitheater under the summit of the mountain, bounded by lofty walls of dolomitic limestone, regularly stratified, presenting splendid examples of folding, he found in fragments of the limestone, among some detritus of serpentine, various limestone blocks that were fossiliferous. The fossils were not as well preserved as could be desired, owing apparently to incipient alteration, but they enabled him to distinguish the following genera: Syringopora, near S. ubdita, (a fine species with the long branches one-sixth to one-third of an inch in diameter, and one-eighth to one-fourth of an inch apart, according to the figure); Halysites; a branching coral supposed to be a Favosites; a joint of a stem of an Actinocrinus; a shell of an Ostracoid, referred to "Cythereis," and a sponge, Lithospongia. The species indicate that the limestone is probably of the age of the later Upper Silurian, or the earlier Devonian. Prof. Gastaldi remarks that the limestone beds are superimposed directly on the serpentine, euphotide, and variolite of the region, in some places with a rather sudden transition from one to the other; but also that at other localities the more recent beds of the pietre verdi zone, that is, the "Calcischist" containing beds of |