24 



NA TURE 



\May i, 1884 



bon under atmospheric pressure, by M. S. YVroblewski. — On a 

 metallic radical, by M. P. Schutzenberger. — Determination of 

 the densities of the vapours of the chloride of glucinium, by 

 MM. L. F. Nilson and Otto Pettersson. — On the neutral molyb- 

 dateofdidymium, and on the equivalence of didymium, by M. Alph. 

 Cossa. — On the curves of solubility of salts, by M. A. Etard. — 

 On the bark of Xanthoxylum caribaum, Lk., as a febrifuge, by 

 MM. Meckel and Fr. Schlagdenhauffen. — On the application 

 of the digester for the destruction of microbes in liquids, by M. 

 L. Heydenreich. — On some siliceous spicules of living sponger 

 obtained from the dredgings executed during the last expedition 

 of the Talisman, by M. J. Thoulet. — On the generic relations 

 oiOrbulina universa with Globigerina, two illustrations, by M. 

 C. Schlumberger. From the comparative study of these organisms 

 the author infers that the dimorphism of the Foraminifera is an 

 initial character resulting from two original forms. — ( >n the action 

 of heat on the phenomena of vegetation : ( 1 ) on the development 

 and direction of the roots ; (2) on the heliotropism of certain 

 plants, by M. A. Barthelemy. — On marine and fresh-water de- 

 posits considered from the economical standpoint, according as 

 they are or are not sulphuretted ; alluvia of the Durance, by M. 

 Dieulafait. — New report on the diamantiferous deposit at Grao 

 Mogol, province of Minas Geraes, Brazil, by M. Gorceix. — On 

 the bones of the head of the Simcedosaurians, and on the various 

 species of this extinct reptile found in the Cernay formations in 

 the Rheims district, by M. V. Lemoine. — Note on the crepus- 

 cular phenomena observed at the Imperial Observatory of Rio 

 de Janeiro during the winter months of 1S83-S4, by M. L. Cruls. 

 — Note on the scientific mission to Cape Horn 1882-S3 in con- 

 nection with the question of the periodicity of barometric 

 oscillations, by M. Ch. V. Zenger. 



Berlin 

 Physical Society, March 21. — Dr. Frolich spoke of some 

 modifications of Wheatstonc's bridge which had been applied to 

 the measurement of the electric resistance of galvanic elements 

 and batteries. Wheatstone's bridge consisted, as was known, 

 of a wire quadrilateral and two wire diagonals. Of the two 

 diagonals one contained a battery of constant electromotive 

 force, the other the galvanometer. In these circumstances 

 the resistances of the four lateral wires showed the proportion 

 W, : W, = W„ : W 4 . For the purpose of measuring the resist- 

 ance in a galvanic battery, the arrangement was so far empiri- 

 cally changed that the battery to be measured was inserted in 

 one of the lateral wires. A second empirical method consisted in 

 inserting the galvanometer into one diagonal wire and interrupting 

 the second ; the battery to be measured was placed in a lateral 

 wire. Dr. Frolich showed that both arrangements were only 

 modifications of Wheatstone's bridge. The way in which these 

 modifications originated might be conceived by supposing that 

 the bridge was formed of cords, and that the angles of the square 

 were successively shifted ; the proportion which applied to 

 Wheatstone's bridge would still hold in the new case. Dr. 

 Frolich laid down a general law applicable to all individual 

 cases. If in a Wheatstone bridge an element be inserted into 

 each wire, while one diagonal wire contained the galvanometer, 

 and the other was interrupted, if, moreover, on opening this 

 wire, the electromotive force in the other diagonal remained 

 unchanged, then the proportion above stated between the resist- 

 ances of the lateral wires would still hold. Whether this general 

 law included such a case as could be applied practically and 

 with certainty to the measurement of the resistance of elements 

 must be determined by experience. — Dr. Frolich then gave 

 a report on the continuation of his measurements of solar 

 temperature. At a former sitting he communicated the measure- 

 ments he had made during the previous year. These measure- 

 ments yielded an almost equal result on June 29 and July I, an 

 increase of solar heat of 6 per cent, over this last estimate on 

 August 14, and a value pretty nearly equal to that of July 1 in 

 the middle of October. Since then doubts had been expressed 

 as to whether the calculated increase of solar heat in August 

 corresponded with the fact, seeing that the amount of the differ- 

 ence was not so much greater than might be accounted for by 

 assuming an error, not easily avoided, in an observation. In 

 opposition to this consideration, Dr. Frolich contended that, even 

 if it were claimed that the difference would have to be three 

 times greater than any error in observation which might probably 

 occur, the increase in August had such a high degree of proba- 

 bility in its favour that one might bet 22J to I for its accuracy. 

 All doubt, however, on the matter was completely removed by 



two measurements Dr. Frolich made on February 19 and March 

 17. Both measurements yielded pretty nearly equal values of 

 solar heat, and one was 15 per cent, higher than the estimate of 

 the middle of October last year. In this case the probable error 

 was surpassed eight times. Dr. Frolich was of opinion that the 

 increase of solar heat in August was connected with an assumed 

 formation of sunspots, and seeing that the spots were bound up 

 with the magnetism of the earth he made inquiries with a view 

 to ascertaining the state of the terrestrial magnetism at that 

 time. From the average of the reports collected by him hk 

 found that in correspondence with the increased solar heat in the 

 middle of August there was a diminution of the earth's magnet- 

 ism.— At the close Dr. Frolich produced a large lump of mag- 

 nesium as the product of an electrolytic industry. The piece 

 was wrought in a factory according to a patented method based 

 essentially on the melting of chloride of magnesium, and decom- 

 posing it in the melted state by an electric current. 



Vienna 



Imperial Academy of Sciences, March 20. — L. Martin, 

 on the polydimensional argument. — R. von Drasche, on some 

 new and less-known ex-European Ascidia. — T. Latschen- 

 berger, on testing and determining ammonia in animal fluids. — W. 

 Fossek, synthesis of dyad alcohols by action of alcoholic potash 

 on aldehydes. — On the action of phosphorus trichloride on 

 aldehyde, by the same. — F. Wiesner, on geotropic curvature 

 of roots. — F. W. Dafert, synthesis of glycuronic acid from man- 

 nite (sealed packet). — K. Olszewski, determination of density 

 and of coefficient of expansion of liquid oxygen. — Determination 

 of the temperature of solidification of some gases and liquids, by 

 the same. 



April 3. — A. Adamkiewicz, preliminary communication on new 

 stainingsof the spinal cord, part ii. ; results obtained by staining the 

 diseased spinal cord with saffronine. — M. Loewit, contributions to 

 theory of blood-coagulation, part i. ; onthecoagulatingpowerof the 

 blood-disks. — A. Lustig, contributions to development of gustatory 

 buds. — T. V. Tanowski, on direct substitution-products of azo- 

 benzene and on an asymmetrical trinitroazobenzene. — E. Witlazil, 

 on polymorphism of Cfuetophorus populi, L. — M. Strainsky, on 

 tides and their reaction on the configuration of the earth's sur- 

 face. — R. Benedikt and K. Hazura, on morin. — R. Benedikt 

 and P. Julius, on diresorcin and diresorcinphthaline. — K. 

 Hazura and P. Julius, on resorcin-ether. — P. Julius, on a new 

 reaction of benzidine. 



CONTENTS Pagh 



Science and Manufactures 1 



Forster's "Strata of the North of England" ... 3 

 Our Book Shelf:— 



Watts's "Manual of Chemistry" 3 



Woodward's "Arithmetical Chemistry" 4 



Reynolds's " Experimental Chemistry " 4 



Letters to the Editor :— 



Reply to Mr. Grubb's Criticisms on the Equatorial 



Coude of the Paris Observatory. — M. Lcewy . . 4 

 On the Motion of Projectiles. — Rev. Francis Bash- 

 forth 5 



The Dry and Wet Bulb Thermometers "Froude." — 



Prof. H. A. Hazen 6 



Extraordinary Darkness at Midday. — Rev. S. J. 



Perry, F.R.S 6 



Intelligence in Animals. — Duncan Stewart ; Dr. 



John Rae, F.R.S 6 



The Absorption of Water by Plants. By Francis 



Darwin, F.R.S 7 



What is a Liberal Education ? By Prof. S. New- 

 comb 9 



The Krakatoa Eruption. By R. D. M. Verbeek . . 10 



The Late Monsieur Dumas 15 



The Earthquake. By W. Topley ; Surgeon-Major 

 W. C. B. Eatwell ; Dr. J. E. Taylor j Albert H. 

 Waters ; Rev. O. Fisher ; G. M. Whipple ; J. 



Edmund Clark 17 



Notes 19 



Our Astronomical Column : — 



The Southern Comet (Ross, January 7) . 21 



The Aspect of Uranus ..." 21 



University and Educational Intelligence 22 



Societies and Academies . . 22 



