So 



NATURE 



March 28, 



191! 



635 tons; London, 1915-16, 453 tons ; Sheffield, 1914-15, 

 395 tons; Malvern Wells, 1915-16, 56 tons. He stated 

 that there was evidence of a general reduction of atmo- 

 spheric impurity during the winter of 1916-17 as com- 

 pared with the preceding one, probably due to reduced 

 consumption of raw coal. Mention was made of cer- 

 tain problems awaiting solution, such as the relation of 

 mipurity to wind and distance from source, also to 

 incidence of disease. Does smoke in the air reduce or 

 increase the number of bacteria? What is the vertical 

 distribution of suspended matter and the selective power 

 of rain or snow \n bringing down impurity? 

 JNIanchestkr. 



Literary and Philosophical Society, March 



Mr. W. 



Thomson, president, in the chair. — E. L. Rhead : The 

 corrodibility of cast-iron. The paper dealt with the 

 effects of the impurities in producing during the solidi- 

 fication of the metal various solutions, in which the 

 impurities were concentrated. This was especially the 

 ■case with the phosphide. The concentration depended 

 on the lower melting point of the solution thus 

 formed. Reference was made to the production of 

 graphite. Specific instances in which the failure of 

 cast-iron vessels was due to the increase in volume 

 resulting from the corrosion, and the influence of the 

 structure due to the segregatioh and coarse 

 graphite, were dealt with ,and specimens shown. 

 Attention was also .directed to the high silicon 

 iron now used for chemical plant, and segrega- 

 tion was shown to take place to a marked extent. 

 Paris. 

 Academy of Sciences, March 4. — M. Paul Painleve in 

 the chair. — The president announced the death of Prof. 

 Blaserna, correspondant of the Academy for the section 

 of physics. — A. de Gramont : The ultimate rays of great 

 sensibility of columbium (niobium) and zirconium.— C. 

 Guichard : A particular class of curves several 

 times isotropic. — W. Kilian : The fauna of the 

 Hauterivian stratum in the south-east of France. 

 — Mr. Amundsen was elected correspondant of 

 the Academy for the section of geography and 

 navigation in succession to the late Dr. Albrecht. 

 — J. F. Ritt : The repetition of rational func- 

 tions.— M. Valiron : Demonstration of the existence, 

 for integral functions, oA paths of infinite determination. 

 — M. Doyere : Remarks on the resistance to motion of 

 i2feometrically similar vessels.- — J. Rey : Entropy dia- 

 gram of petrol.-^Sir R. Hadfield, C. Cheneveau, and Ch. 

 Geneau : The magnetic properties of manganese and of 

 some special manganese steels. Manganese, when 

 freed from occluded gases, is paramagrtetic. Data are 

 given for manganese-carbon steels, and steels con- 

 taining, in addition to these two elements, nickel, 

 tungsten, chromium, and silicon.— A. Valeur and 

 E, Luce : The reduction of the CHJ group joined to 

 nitrogen.^ — G. Fouque : Dicyc'ohexylamine, its solid 

 hydrate and alcoholate.^ — P. Russo : Geology of the plain 

 of El Hadra, western Morocco.— J. Repelin : New 

 species of the genus Entelodon. 



March 11. — M. Paul Pain1ev6 in the chair.— Ch. 

 Lallemand and J. Renaud : The substitution of civil time 

 for astronomical time in nautical almanacs. At sea 

 sailors use civil time, but for their observations make 

 use of tables where astronomical time is employed, and 

 it is desirable that this possible source of confusion 

 should be removed. Both the French and British 

 Admiralties considered the proposal favourably, and the 

 volume of the " Ephemerides nautiques " now in pre- 

 paration (1920) will have civil time substituted for astro- 

 nomical tinie. — W. KiliFn : New remarks on the fauna 

 of the Hauterivian, Barremian, Aptian, and Albian 

 strata in the south-east of France. — M. Tilho was 

 elected a correspondant for the section of geography and 

 navigation in succession to the late General Gallieni. — 

 NO. 2526, VOL. lOl] 



Tr. Lalesco : A point of the theory of nuclei capable of 

 symmetry. — M. Brillouin : Biaxial media. — F. Cloup : 

 Tempering and work hardening in carbon steels. — M, 

 Travers : The colorimetric estimation of tungsten. The 

 method is based on the reduction of- tungstic acid by 

 titanous chloride to a blue oxide, which, under certain 

 conditions, . remains in colloidal suspension. The re- 

 action cannot be ajjplied if vanadium, phosphorus, or 

 molybdenum is present. — J. H. Sinclair; The age of 

 the sandstones of French Guinea. — L. Gentil : The age 

 of the strait connecting the Mediterranean and' the 

 Atlantic through Morocco in the Miocene epoch. — .\. 

 Guebhard : Remarks on the "6corce resistante." — G. 

 Reboul : A method of predicting barometric variations. 

 — J. Amar : The law of cicatrisation of wounds. The 

 number of factors is so large, and the phenomenon so 

 complex, that it is doubtful whether any attempts at 

 mathematical expression can be successful. — B. QesHn 

 and J. WoKf : New observations on the degradation of 

 inulin and " inulides " in the root of the chicory. 



BOOKS RECEIVED. 



The Theory of Electricity. By G. H. Livens. Pp. 

 vi + 717. (Cambridge: At the University Press.) 305. 

 net. 



Electricity Meters : Their Construction and Manage- 

 ment. By C. H. W. Gerhardi. Second edition. Pp. 

 XX + 504. (London : Benn Bros., Ltd.) 15s. net. 



Stanford's War Maps. No. 27: Europe and North- 

 ern Asia. (London : E. Stanford, Ltd.) 



Some Problems of Modern Industry. By W. L. 

 Hichens. Pp. 61. (London: Nisbet and Co., Ltd.) 

 6d. net. 



Proceedings of the Aristotelian Society. N.S. Vol. 

 xvii. (London : ^^■il]iams and Norgate.) 12s. 6d. net. 



CONTENTS. PAGE 



Recent American Text-books in Agriculture. By 



Dr. E.J. Russell, F.R.S 61 



Essences and Varnishes. By C. S 62 



Our Bookshelf . 63 



Letters to the Editor:— 



The Stimulation of Plant-growth by Electric Fields.— 



V. H. B, and G. W. O. H 64 



Does the Indigenous Australian Fauna Belong to the 

 Tertiary ?— Prof. H. F. Cleland ... .64 



The Bombardment of Paris by Long-range Guns. 



By Sir G. Greenhill, F. R S. . . 65 



Colloids and Chemical Industry. By Prof. W. C. McC. 



Lewis 66 



Dr. G.J. Hinde, F.R.S 67 



Notes 68 



Our Astronomical Column : — 



Planetary Perturliatiohs and ^Ether-drift 72 



Perturbations of Neptune's Satellite 72 



Motion of Our Stellar S) stem ... 72 



Food Rations for Manual Workers and Scientific 



Laboratories . . . . 72 



The Palms of Seychelles and the Mascarenes. By 



Dr. W. Botting Hemsley, F.R.S. 73 



National Laboratories and Industrial Development. 

 I. By Sir R. T. Glazebrook, C.B., F.R.S. ... 74 



University and Educational intelligence 77 



Societies and Academies 7^ 



Books Received . 80 



(Index.) 



Editorial and Puhlishing Offices: 



MACMILLAN AND CO., Ltd., 



ST. MARTIN'S STREET, LONDON, W.C.2. 



Advcrtiseuieiits and business letters to he addressed to the 

 Publishers. 



Editorial Communications to the Editor. 

 Telegraphic Address : Phusis, London. 

 Telephone Number : Gerr.ard 8830. 



