March 24, 19 10] 



NA TURE 



119 



of speech there must be a compromise. The author laid 

 stress upon the fact that his method of calculation could 

 be taught to quite non-mathematical people. — Prof. C. H. 

 Lees : The laws regarding the direction of thermo-electric 

 cuTents enunciated by M. Thomas. — H. R. Nettleton : 

 New method of determining thermal conductivity. 



Mineralogical Society, March 15. — Prof. W. J. Lewis, 

 F.R.S., in the chair. — G. W. Grabham : A new form of 



petrological microscope, with notes on the illumination of 

 microscopic objects. The new instrument, which is of the 

 " Dick " or " English " pattern, has a focussing sub- 

 stage carrying a series of condensers mounted on a triple 

 nose-piece, each capable of being inserted in the axis of 

 the instrument. A new explanation was given of the 

 " Becke " or bright-line effect, especially applicable to 

 parallel polarised light traversing mineral sections, which 

 meet along inclined junctions.— W. F. P. McLintock : 

 Datolite from the Lizard district. Datolite, which is 

 associated with calcite, chalcopyrite, and natrolite (rare) 

 in veins and geodes at the junction of the serpentine and 

 hornblende schist. Pare Bean Cove, Mullion, Lizard dis- 

 trict, Cornwall, occurs in crystals measuring up to 2 cm. 

 along the fe axis, and displayed fourteen forms, of which 

 two were new. .\n analvsis gave SiOj, 37-45 ; CaO, 3467 ; 

 Fe,0. and Al^O^, 0-57'; B^O,, 21-87; H^O, 5-67; total, 

 100-23. — ^Arthur Russell : Additional notes on the occur- 

 rence of zeolites in Cornwall and Devon. The occurrence 

 Df heulandite, a mineral hitherto not recorded from Corn- 

 wall, at Carrick Du Mine, St. Ives, Cornwall, was 

 iescribed ; also of chabazite and heulandite at the Ramsley 

 Mine, South Tawton, Devon. — Dr. J. W. Evans : A 

 Tiodification of stereographic projection. Faces below the 

 jlane of projection are represented by the same points as 

 jarallel faces above it, upper faces being distinguished by 

 i plus, and lower faces by a minus, sign. — Dr. J. W. 

 Evans : Axes of rotaton.- symmetry. Coincidence is com- 

 )lete or codirectional when equivalent lines and their 

 jHrections coincide, incomplete or contradirectional when 

 l^quivalent lines coincide, but equivalent directions of uni- 

 jerminal lines are opposed ; in both cases it is colinear. 

 if a minimum rotation of irin result in codirectional, 



ontradirectional, or colinear coincidence, the axis of rota- 



Mon has codirectional, contradirectional or colinear 



-etry, with cyclic number. n. — Prof. H. L. Bowman 



■red models illustrating space-lattices and Sohncke's 



vjAi.t-systems. 



DimLIN. 



Royal Dublin Society, February 22.— Mr. R. M. Barrington 



\ the chair. — Prof. W. Brown : Chrome-steel magnets. 



light steels containing from 1-75 to 922 per cent, of 



hromium were tested for magnetic moment per gram, the 



est result being obtained with a magnet which contained 



lx>ut 2-5 per cent, of chromium. — ^\V. J. Lyons : The 



istribution of mean annual rainfall over the counties of 



•ublin, Wicklow, Kildare, and Meath. The rainfall over 



lis area varies from below 28 inches to probably more 



lan 60 inches in a very marked manner, closely related 



> the very striking orographical features of the area. The 



ithor suggested that the recognised action of hills in 



ducing condensation by causing ascensional currents was 



>t an adequate explanation of the marked increase found 



the rainfall of hilly districts. He thought it probable 



lat mountains facilitated the processes of rain develop- 



ent, apart from any influence on condensation. — Prof. 



• F- Barrett : A simple form of open-scale barometer. 



1 form this instrument resembles an air thermometer, 



ily that it indicates variations of atmospheric pressure 



id is almost insensible to changes of temperature. This 



accomplished by making use of a Dewar's liquid-air 



tsk as the air receptacle, into which is sealed a quill 



ass tubing containing an index of a dense non-conducting 



luid. The tube is open to the air at one end, and is 



aled into a wider glass tube which surrounds it, and 



Jm which the air has been exhausted as completely as 



ssible. It is found in practice that the readings corre- 



and fairly well with those of an ordinary barometer, 



d as it can be made as sensitive as desired by altering 



; ratio of the capacities of the bulb and index tube, it 



adapted for domestic use as a weather-glass, and claims 



be nothing more. 



NO. 2108, VOL. 83] 



Paris. 



Academy of Scicn cs, March 14. — M. tmiie Picard in 

 the chair. — Henri and Jean Becquerel and H. Kamerlingh 

 Onnos : The phosphorescence of uranyl salts at very low 

 temperatures. The changes observed in the absorption 

 spectra at temperatures down to that of liquid air have 

 been described in a previous paper. In the present paper 

 details of the spectra are given for the temperatures of 

 80° C. absolute (boiling nitrogen) and 14° C. absolute 

 (solid hydrogen). The bands approach asymptotically a 

 limiting position as the temperature is lowered. A very 

 strong magnetic field (35,000 Gauss) is without influence 

 on the spectra. Ordinary phosphorescent spectra appear 

 to be due to the effect of traces of impurities in the phos- 

 phorescent substance ; this is not the case with uranyl 

 salts ; the spectra appear to be due to the uranium itself. 

 — H. Deslandres and P. idrac : The spectrum of the 

 comet igioa. The arrangement of the spectrograph used 

 is described, and the wave-lengths of the lines observed 

 given. The bands of hydrocarbons and cyanogen were 

 identified. — ^J. Boussineeq : The vertical propagation, at 

 great depths, of the movement of waves by emersion in 

 the case of a canal or basin indefinite horizontalh'. — MM. 

 Haller and Ed. Bauer : The alkylation of the fatty ketones 

 by the use of sodium amide. The decomposition of the 

 hexa-alkylketones. Diethylketone has been methylated by 

 sodium amide and methyl iodide, ethyl-isopropylketone, 

 di-isopropylketone, a high boiling condensation product, and 

 tetramethyl-ethy Ike tone, being produced. The hexa-alkyl- 

 acetones are split up by sodium amide, a trialkylmethane 

 and trialkylacetamide arising from the reaction. — Prof. 

 Hittorf was elected a foreign associate. — Charles Nord- 

 mann : The absorbing atmospheres and the intrinsic 

 luminosities of some stars. — ^Jules Baillaud, J. Chatelu, 

 and M. Giacobini : Observation of a minor planet at the 

 Observatory of Paris. The traces of this planet were first 

 noticed by Jules Baillaud on a negative of the international 

 chart of the sky taken on March 3. Observations are 

 tabulated for March 3, 5, 7, 8, 10, and 11. — Fr^d^ric 

 Riesz : Certain systems of functional equations and the 

 approximation of continued functions. — L. Remy : The 

 algebraic surfaces representable on that of Kummer. — H. 

 Larose : The equation of telegraphists. — E. Estanave : 

 The simultaneous production of stereoscopic relief and of 

 changing aspect in the photographic image. — Pierre Weiss 

 and Kamerlingh Onnes. The saturation intensity of 

 magnetisation at very low temperatures. The intensities 

 of saturation have been measured at the ordinary tempera- 

 ture and at the temperature of boiling hydrogen (20" C. 

 absolute) for nickel, iron, and magnetite. The results for 

 cobalt were not satisfactory. — Pierre Weiss and Kamer- 

 lingh Onnes : The magnetic properties of manganese, 

 vanadium, and chromium. For these metals at the 

 temperature of solid hydrogen (14° C. absolute) there was 

 expected either the appearance of ferromagnetic phenomena 

 or a paramagnetism considerably increased according to 

 Curie's law. It was found experimentally that neither of 

 these effects was produced, the magnetic phenomena re- 

 maining very slight. The theoretical consequences of these 

 facts are discussed. — P. Vaillant : A particular case of 

 evaporation. A study of the diffusion of the vapour arising 

 from a liquid in a cylindrical tube the length of which was 

 great in proportion to its diameter. — Ch. Fery : A new 

 reflectometer. A hemispherical cavitj* is formed in a block 

 of plane glass, and the hole exactly filled by a hemi- 

 spherical block of glass of the same curvature. The drop 

 of liquid the refractive index of which is to be measured 

 is placed between the two blocks, and the radius of the 

 dark ring formed by total reflection measured. From this 

 and the corresponding radius of the dark ring when air 

 is between the two blocks the index of refraction can be 

 determined with an accuracy of about 0005. — L. Bioch : 

 Chemical actions and ionisation by bubbling. It is shown 

 that the ionisation produced when gases are evolved from 

 a liquid is the result of actions in the liquid surface. — 

 O. Boudouard : The testing of metals by the study of 

 the damping of vibratory movements. — M. Vfezes : The 

 analysis of essence of turpentine by curves of miscibility. 

 The author's results generally confirm those of M. Louise, 

 but some differences are pointed out. — M. Lecoq : A 

 colloidal solution of pure metallic arsenic. A colloidal 



