456 



NA TURE 



Tarch lO, i< 



plate in front of the thermo-electric pile which he had made use of 

 in his first measurements. He had been induced to remove the 

 rocI<-saIt plate by the conviction that after a time rock-salt 

 developed a quality of transmissibility which was not identical 

 both for luminous and for non-luminous heat. The bare thermo- 

 electric pile showed itself by oft -repeated proofs to be constant 

 towards the rays of a Leslie cube. The relation of the rays 

 from the blackened side of the cube to the rays from the white side 

 continued invariably the same. The same constancy was mani- 

 fested in the registrations of the thermal element towards the 

 luminous heat of a white-glowing platinum chimney, wdiich was 

 uniformly heated by two gas-flames. The observations of solar 

 heat were made on perfectly bright days and under a per- 

 fectly clear atmosphere, the thermo-electric pile being directed to 

 the sun under very different heights, as far as io°, and exposed 

 to the sun till the diversion of the galvanometer had become 

 constant. The values obtained on the various day.? and under 

 different solar positions were graphically delineated, on the 

 supposition that the absorption of the atmosphere was an expon- 

 ential function of its density. The result came out that the 

 " curve " was practically a straight line, or a line concave or 

 convex to so small a degree as to deviate but very little from a 

 straight line. When the curve was lengthened till it met the per- 

 pendicular co-ordinate, then the intersecting point representing 

 the magnitude of the solar heat was the same for all days of 

 observation. The deviating results of Mr. Langley and Messrs. 

 Angot and Crova were explained, in part from the fact that in 

 their calculation the reflection of the thermal rays in the dif- 

 ferent atmospheric strata had not been taken account of, and 

 in part from the fact that the different atmospheric strata were 

 assumed to be parallel, and so their incurvation was left out 

 of account. Notwithstanding the circumstance that the absorp- 

 tion by the atmosphere was different for the different kinds of 

 rays, and also different from day to day, yet was the " curve," 

 the co-ordinates of which were represented by the observed heat 

 and the abscissa; by the logarithms, without exception, a straight 

 line. This empirically ascertained fact was the main result of 

 the whole series of investigations extending over three years. 



Physical Society, February 4. — Prof Helmholtz in the 

 chair. — Dr. Sprung described the barograph designed by him, 

 which avoided the errors of the older balance-barometer 

 (first constructed in 1760 by Samuel Moreland) by making the 

 barometer work on a resting horizontal beam, which through 

 horizontal automatic displacement of a sliding weight was kept 

 always in exact equilibrium. The travelling vertical tread- 

 wheel constantly marked its position on the writing-table of the 

 instrument. Seeing, moreover, that this displacement of the 

 tread-wheel was effected by a clockwork, any disturbance that 

 might arise from its rubbing against the barometer was com- 

 pletely precluded. The automatic equilibration of the beam of 

 the balance was produced by an electric current. The speaker 

 had quite recently instituted a series of the most various experi- 

 ments, by which he demonstrated how the registering balance 

 designed by him was with great advantage available for a large 

 number -of physical investigations : how, for example, he was 

 able by his balance to permanently register the state of the quick- 

 silver in the barometer ; the progress of the evaporation of alco- 

 hol ; the discharge of a fluid from a capillary tube ; the change 

 of intensity in an electric current ; the evaporation of water 

 through a clay-ball ; the changes of density in the atmospheric 

 air recorded by the variations of rise on the part of a large glass 

 ball ; and phenomena connected with permanent change of 

 weight. The registering balance, which was being executed by 

 the mechanician Fues in Berlin, allowed, in short, a large series 

 of physical processes to be automatically recorded, and would 

 prove highly useful in many physical investigations. — Prof 

 Helmholtz, by an experiment, demonstrated the great cohesion 

 of an air-free column of water. A siphon-shaped glass tube, the 

 longer leg of which was closed and the shorter one open, was 

 filled with quicksilver, and above the quicksilver there was 

 superposed a small quantity of distilled water. If the filling was 

 effected without admission of air, then, on the tube being placed 

 in an upright position, the water adhered to the closed end, and 

 its adhesion supported the quicksilver column, which was longer 

 than the barometer height. The speaker now brought the open 

 end of the siphon tube into communication with an air-pump, 

 and caused to be pumped out as much as down to 2 mm. 

 pressure, but even then the cohesion of the water supported the 

 quicksilver column. Only by shaking was the water colunm 

 shattered, and the quicksilver immediately sank. If there was 



no shaking, the apparatus continued for an unlimited length of 

 time unchanged. This contrivance should serve the purpose of 

 electrolysing air-free water and ascertaining the strength of the 

 current under which gas bubbles developed themselves by 

 electrolysis. The experiment showed that on the transmission 

 of a current of 2 volts the water continued adherent. The 

 depression of the quicksilver column in consequence of gas 

 development occurred, however, in an experiment with a current 

 of 2'I5, and in another with a current of 2'i8 volts. 



February 18. — Prof Schwalbe in the chair. — Dr. Friilich 

 spoke of his measurements of the solar heat in the years 1883, 

 1S84, and 1886, and refuted at length the objections which had 

 been raised against these measurements by MM. Vogel, Langley, 

 Angot, and Crova. In the discussion following thereon. Dr. 

 Kiinig stated that experiments carried out in the Physical 

 Institute wiih a Langley bolometer indicated that very consider- 

 able inlluence is exercised by the air-currents on this delicate 

 measuring-instrument. 



BOOKS AND PAMPHLETS RECEIVED 



Cal.ilogue of the Fossil Mammalia in the : 

 part iv. ; R. Lydekker. — Practical Electric 

 Treatise on .\lgebra : Profs. Oliver, Wait, 

 tributions to Meteorology, chap. ii. revised 

 —The Game of Logic : L. Carroll (M 



3rilish Museum, Natural History, 

 Ity : W. E. Ayrton (Cassells).— A 

 and Jones (Finch, Ithaca).— Con- 

 edition : E. Loomis(New Haven). 

 1). — Bees and Bee-keeping, 



Vol. 11. parts 5 and 5: F. R. Cheshire (U. Gill).— British Dogs, parts 2-5 : 

 H. Dalziel (U, Gill).— Fancy Pigeons, 3rd edition: J. C. Lyell (U. Gill).— 

 Vegetable Diology : Dr. T. W. Shore (Churchill).- Anecdota O.xoniensis ; 

 Alphita : edited by J. L. G. Mowat (Clarendon Press).— Journal of the 

 Anthropological Institute, February (Triibner). — Outlines of Lectures on 

 Physiology: T. W. Mills (Drysdale, Montreal).— Schools of Forestry in 

 flermany : Dr. J. C. Brown (Oliver and Boyd).— Social History of the 

 Races of Mankind, 2nd division : A. Featherman (Trubner).- Cotnplete 

 Hand-bi:iok on the Management of .A.ccumuIators, 2nd edition ; Sir D. 

 Salomons (Whittaker). — The Encyclopsedic Dictionary, vol. vi. part i 

 (Cassells). — Journal of the Chemical Society, March iGurney and Jackson). 

 — F.nlletin of the American Geographical Society. Nos. 4 and 5, 1885 (New 

 York) —Annual Report of the Proceedings of the Sussex Association for the 

 Improvement of Agriculture, 1886. — Journal of the Asiatic Society of Bengal, 

 vol. Iv. part 2. — Aborigines of Hispaniola; H. Ling Roth (Harrison). — 

 Bibliography and Cartography of Hispaniola : H. Ling Roth. 



CONTENTS PAGE 



The Aurora Borealis. lly A. M. Gierke, (llliis- 



Irated) 433 



The Butterflies of India. 15y H. J. Elwes .... 436 

 Our Book Shelf: — 



Rosser : "The Deviation of the Compass in Iron 



Ships considered Practically " 437 



Simson : " Travels in the Wilds of ICcuidor ' . . . 437 

 Letters to the Editor : — 



Tabasheer. — Henry Cecil 437 



Temperature and Pressure in Jamaica. — Maxwell 



Hall 437 



Electricity and Clocks. — Horloge 438 



Top-shaped Hailstones. — T. Spencer Smithson 438 



The Present Southern Comet.— A. W. R 438 



The Earthquake.— Rev. S. J. Perry, F.R.S. . . 438 

 Cerebral Localisation, I. By Prof. E. A. Schafer, 



F.R.S. (IllustratcJ) 43S 



The University Colleges 441 



The Earthquake in Switzerland 442 



Notes 442 



Our Astronomical Column : — 



Solar Activity in 1SS6 445 



Comet 1SS7 ./(Barnard, February 15) 446 



The Warner Observatory 446 



Astronomical Phenomena for the Week 1887 



March 13-19 446 



Geographical Notes 446 



On Radiant Matter Spectroscopy : — Examination of 

 the Residual Glow, II. By William Crookes, 



F.R.S. [I/luslralfJ) 447 



University and Educational Intelligence 451 



Scientific Serials 451 



Societies and Academies 452 



Books and Pamphlets Received 456 



