February 24, 1910J 



NA TURE 



509 



average.— Colonel H. E. Rawson : The North Atlantic 

 anticyclone. The author has examined the " Synchronous 

 Weather Charts of the North Atlantic " published by the 

 Meteorological Ofhce for the months of September, 1882, 

 to .August, 1883, and has analysed the traclis of the centres 

 of high-pressure areas during that period. He finds that 

 it is very rare for an individual system which has traversed 

 the American continent to cross the ocean from land to 

 land. In every month centres of high areas which have 

 drifted across America and have travelled out on to the 

 ocean are found coalescing there with one another or with 

 the centres of the persistent Atlantic anticyclone. From 

 mid-February to mid-September the charts indicate that on 

 arrival on our coasts systems extend westwards, and their 

 centres reverse their easterly movement and drift to the 

 west, while in June and July the centres of high areas 

 form over the ocean within tlie Atlantic anticyclone rather ' 

 than drift into it from the American continent. 



Institution of Mining and Metallurgy, February 17. — 1 

 Mr. Edgar Taylor, president, in the chair. — Bede Colling- 

 ridgre : Errors due to the presence of potassium iodide in 

 testing cyanide solutions for protective alkalinity. The re- 

 sults of experiments made by the author show that 

 potassium iodide exercises an important influence on cyanide 

 solutions, especially on sol itions which contain no protec- 

 tive alkali, since in testing these in the presence of potas- 

 sium iodide they show protective alkalinity. This fact^ is 

 of considerable interest in cyanide plants, because cyanide 

 decomposes more rapidly in solutions deficient in protective 

 alkalinity than in those protected by an alkali, and the 

 method adopted by the author for testing without potassium 

 iodide would therefore imply a marked saving of cyanide 

 in the case of large plants. — k. R. Andrew : The detection 

 of minute traces of gold in country rock. In the course of 

 investigations made for the purpose of determining the 

 presence, or otherwise, of minute traces of gold in the 

 shales and greenstone of Merionethshire, the author found 

 that he was unable to believe in the trustworthiness of the 

 methods usually adopted for that purpose, particularly as 

 regards the possibility of obtaining litharge Or any sort of 

 lead absolutely free from gold and silver. On that account 

 he claims that no credence should be given to any alleged 

 detection of minute traces of gold in country rock unless 

 accompanied by a full account of the means by which the 

 purity of the litharge is assured. — W. A. MacLeod : The 

 surface condenser in mining power plant. The author con- 

 ducted a number of tests on the winding engines of a 

 mine with which he was connected, the results of which 

 are embodied in this paper, together with a vast amount 

 of other information concerning the relative consumptions 

 and efficiencies of condensing and non-condensing engines. 

 He found that the employment of condensers was distinctly 

 beneficial in both respects, even under the intermittent con- 

 ditions attaching to most mining power plants, and the 

 results of his investigation have enabled him to determine 

 with some exactness the leading features to be emphasised 

 in the laying down of a condensing plant suitable for work 

 of a more or less intermittent nature, as is the case of 

 winding engines. 



Cambridge. 

 Philosophical Society, lanuary 24. — Dr. Hobson, vice- 

 president, in the chair. — R. R. Mines : The relative 

 velocities of diffusion in solution of rubidium and csesium 

 chlorides. The rates of diffusion of salts into a gelatine 

 jelly were compared by measurement of the progressive 

 changes in the electrical conductivity at a fixed distance 

 below the surface of the jelly when in contact witli deci- 

 normal solutions of the salts. The concentration of salt 

 corresponding to each reading was obtained from Kohl- 

 rausch's tables. Experiments carried out with lithium, 

 sodium, and potassium chlorides gave results which agree 

 with the values found by previous observers for the relative 

 rates of diffusion of these salts in aqueous solution. This 

 was considered to justify the extension of the method to 

 rubidium and c;esium chlorides, as to the rates of diffusion 

 of which no data were available. Rubidium chloride was 

 found to diffuse slightly faster than potassium chloride, and 

 CEesium chloride slightly faster than rubidium chloride. 

 — L. Southerns : Experimental investigation as to depend- 



NO. 2104, VOL. 82] 



ence of the weight of a body on its state of electrification. 

 — Miss D. B. Pearson : Note on an attempt to detect 

 a difference in the magnetic properties of the two kinds 

 of ions of oxygen. 



P.^RIS. 



Academy of Sciences, February 14. — M. Emile Picard 

 in the chair. — G. Lippmann : A seismograph with a liquid 

 column. A T'^tube, full of water, is connected at each end 

 with two basins of the same liquid. The changes of level 

 in the arm of the T-tube are indicated by a thin disc of mica, 

 connected through a suitable mechanism to a mobile mirror. 

 To avoid friction, the disc does not touch the sides of the 

 tube. Owing to this, slow changes of the vertical are not 

 recorded by the instrument. The apparatus has the advan- 

 tage that its period is invariable, depending only on the 

 dimensions originally chosen, and the preliminary adjust- 

 ments are much simpler than in the ordinary form of 

 seismograph. — The perpetual secretary read a telegram from 

 Dr. Charcot, summarising the work achieved by the 

 Antarctic expedition. — Ernest Esclangon : The transforin- 

 ations of the Innes comet (igioa). Two diagrams of this 

 comet are given, showing its appearance on January 22 and 

 30. Although there is no doubt that real transformations 

 of considerable magnitude took place in this comet between 

 the above dates, it is shown that an important part of the 

 modifications observed, especially as regards the shape, is 

 to be attributed to the changes in the angle at which it was 

 observed. Observations of position are given for January 

 22 and 30, the conditions being especially good, and for 

 Februarv 9. — J. Comas Sola: The figure of the comet 

 igioa. Photographs were taken daily commencing January 

 20, and the resuhing negatives discussed. — M. Borrelly : 

 Observations of the comet 1910a, made at the observatory 

 of MarseTlles with the comet finder of 16 cm. free aperture. 

 Positions are given for February 4. ;. 7. 8. 10, and 11. — 

 Emile Borel : The definition of the definite integral. — J. Le 

 Roux : Positive quadratic forms and the principle of 

 Dirichlet. — Farid Boulad : The disjunction of the variables 

 of equations nomographically rational of superior order. — 

 Carlo Bourlet : The resistance of the air. — Mme. P. Curie 

 and \. Debierne : Polonium. Starting with several tons 

 of uranium mineral residues a preliminary treatment with 

 hydrochloric acid furnished about 200 grams of_ material 

 with an activity about 3500 times that of uranium, this 

 activity being due to polonium. The hydrochloric acid solu- 

 tion was treated with ammonia to eliminate copper, the 

 hydrates boiled with soda to dissolve lead, and then further 

 treated with ammonium carbonate to dissolve uranium. 

 The final residue of insoluble carbonates, obtained after 

 several repetitions of these processes, were dissolved in 

 hydrochloric acid and treated with stannous chloride. The 

 original activity was concentrated in the final precipitate, 

 which weighed about i gram. This was re-dissolved in 

 hydrochloric acid, precipitated with hydrogen sulphide, the 

 sulphides washed with sodium sulphide, and re-dissolved and 

 again precipitated with stannous chloride. The final pro- 

 duct of this lengthy series of operations weighed some milli- 

 grams, and was shown by spectrum analysis to contain 

 mercury, silver, tin, gold, palladium, rhodium, platinum, 

 lead, zinc, barium, calcium, and aluminium. The further 

 purification presented great difficulties, but by electrolysis 

 the activity was concentrated into about 2 milligrams of 

 material. Activity measurements proved this to contain 

 about o-i mgr. of polonium, and this is the quantity which 

 ought to be found according to theory in two tons of a 

 good pitchblende. Some lines in the spectrum are given 

 which are probably due to polonium. The production of 

 helium was proved, amounting to 1-3 cubic millimetres 

 after 100 days, the theory requiring i-6. An abundant 

 disengagement of ozone was generally found near the sub- 

 stance.— L. Decombe : The measurement of the index of 

 refraction bv means of the microscope. A modification of 

 Brewster's method. The liquid is placed between a plane 

 and a plano-convex lens. In monochromatic light the 

 refractive index can be determined to about 0001. — P. Roger 

 Jourdain : The alumina arising from the oxidation of 

 aluminium amalgam in air. — Marcel Delepine : The 

 dimeric aldehvde of crotonic aldehyde and the corresponding 

 acid. .\ method of obtaining this' substance with fair yields 



