462 



NA TURE 



[September 9. 1S9; 



by a magnet. The fourth kind appears at the openings in a 

 Holtz's funnel-tube ; it produces no fluorescence, but can be 

 deflected by a magnet. 



A serious state of things was revealed by Prof. A. Johnson 

 in his paper on a Canadian and Imperial Hydrographic Survey. 

 He said that in some parts of the St. Lawrence basin places had 

 been found where the depth of water, charted at five fathoms, 

 was not more than three fathoms, and navigation was thereby 

 rendered dangerous. A committee has been appointed to con- 

 sider the question of approaching the Canadian Government 

 with reference to a new hydrographic survey. 



On Monday the section met in two departments, devoted to 

 mathematics and meteorology respectively. In the mathe- 

 matical department Dr. Harris Hancock gave a short account 

 of the historical development of Abelian Functions, and the com- 

 plete paper will be published as one of the reports of the Asso- 

 ciation. Prof. Henrici proposed a new notation to denote the 

 different products of vectors, which consists in using square 

 brackets for vector products and round brackets for scalar pro- 

 ducts. He likewise advocated the adoption of Heaviside's term 

 "ort" for a vector, the tensor of which is the number i. 

 Prof A. Macfarlane read a communication on the solution of 

 the cubic equation, in which he explained how the two binomials 

 in Cardan's formula may be treated as complex quantities, either 

 circular or hyperbolic ; all the roots of the cubic can then be 

 deduced by a general method. Prof Michelson described some 

 new Harmonic Analyses made by himself and Mr. S. W. 

 Stratton with an instrument which is capable of rendering 80 

 terms of a Fourier series and of checking the accuracy of its 

 own work. The only limit to the number of terms obtainable 

 is the expense of making the instrument. 



In the department of meteorology, Dr. van Rijckevorsel 

 pointed out that the curves of daily temperature for the different 

 meteorological stations in Europe indicate a possible division of 

 the continent into two regions with marked differences of 

 climate. The eastern region includes Russia and adjacent 

 countries, the rest of the continent being in the western region. 

 Small irregularities, such as secondary maxima and minima, are 

 reproduced in all the curves for places in the same region, and 

 serve to show that the temperatures are determined by external 

 causes operating over the whole area. Mr. F. N. Denison 

 described observations on "seiche" movements on Lakes 

 Ontario and Huron, obtained by means of a tidal gauge. Mr. 

 A. L. Rotch reported progress made during the year in the 

 exploration of the air by means of kites. Meteorographs have 

 been raised to a height of 8740 feet above the Blue Hill 

 Observatory, and important information has been obtained con- 

 cerning humidity, changes of temperature and wind in free air. 

 The value of these results in aiding the forecasting of the weather 

 is so great that the United States Weather Bureau has taken up 

 the subject. Prof Marvin described his experiments with tail- 

 less kites, and afterwards exhibited one in flight in the University 

 grounds. 



In electricity, several forms of apparatus for mapping out the 

 form of an alternate current wave were described and exhibited. 

 In the instrument of Prof. Rosa a contact revolving on the 

 dynamo shaft puts a point in the circuit into contact with a 

 potentiometer at any phase of the revolution. By means of 

 an electro-magnetic ratchet arrangement the contact can be 

 advanced in phase by small equal amounts, and the same 

 current similarly rotates a revolving cylinder on which the 

 length of wire necessary for a balance on the potentiometer 

 is automatically recorded. Mr. Duddell makes use of the force 

 urging a straight conductor carrying a current and stretched in 

 a magnetic field ; two parallel phosphor-bronze strips are placed 

 in a strong magnetic field and attached to a mirror, so that 

 when the alternating current goes up one of these strips and 

 down the other one, the mirror is deflected. Prof. Braun uses 

 a kathode ray instead of a strip, and puts it in a magnetic field 

 set up by the alternating current ; the ray is thus deflected and 

 follows every pulsation of the current. The source of luminosity 

 in the electric arc has been investigated by Prof. Henry Crew 

 and Mr. O. H. Basquin. They maintain an arc between an 

 iron rod and a rotating iron disc by a rapidly intermittent 

 electric current, and observe the arc in the intervals when 

 no current is passing. It is found that the luminosity is of 

 two kinds, a bright cloud yellow persisting some time and a 

 much fainter and rapidly evanescent blue flame ; the spectra 

 of these two portions differ in the distribution of intensity 

 of their lines. 



The Electrical Standards Committee report that they have 

 decided to undertake the experiments necessary for the specifi- 

 cation of the standard of electric current, which will be conducted 

 by Profs. Ayrton and J. V. Jones. 



At Wednesday's sitting. Prof. Ramsay described experiments 

 on the refractivity of mixtures of gases, from which it appears 

 that an expansion takes place on mixing hydrogen and helium, 

 and a contraction on mixing nitrogen and oxygen. Prof. 

 Fitzgerald suggested that the viscosity of mixtures of gases 

 should be more fully examined. Prof. Lodge described 

 Zeeman's discovery of the effects of magnetism on spectral 

 lines, and discussed the nature of the dark space between the 

 two lines into which the originally single band is split. Profs. 

 Lodge, Michelson and Runge were agreed that this space is a 

 part of the Zeeman phenomenon, and is not produced merely 

 by the absorption of light in the region round the flame. Several 

 papers on galvanometry were communicated by Prof. Ayrton 

 and Mr. Mather. In the discussion on papers by Prof. Callendar 

 and Mr. Barnes, and Messrs. Spiers, Twyman and Waters, on 

 Clark cells, it was stated by Prof. Webster, that Clark cells 

 with cadmium electrodes in place of zinc are as trustworthy and 

 easily set up as the older form. Such cells have a much 

 smaller temperature coefficient than zinc-cells. 



The meeting concluded with a paper by Mr. J. W. 

 Edmondson, read by Prof. Webster, on spark-length and 

 potential relations in air and dielectric liquids. For air a 

 hyperbolic formula apparently fits the results in the case of 

 spheres of 3 cm. diameter. 



A vote of thanks to the President, moved by Prof. Ayrton 

 and seconded by Prof. Lodge, brought the proceedings of the 

 section to a close. 



NO. 1454, VOL. 56] 



CHEMISTRY AT THE BRITISH 

 ASSOCIATION. 

 'X'HE meetings of the Chemistry Section were usually well 

 -•- attended throughout the whole of the somewhat protracted 

 sittings at Toronto. A large number of the chemists of Canada 

 and of the United States were present, and added much to the 

 interest of the meeting, both within and without the section 

 room. The section only participated, and that in an informal 

 way, in one united discussion, which took place between 

 Sections I and K on the chemistry and structure of the cell. This 

 was opened by Prof. Meldola in a very striking and suggestive 

 paper on the rationale of chemical synthesis. 



In connection with the section an important new committee 

 has been appointed, under the chairmanship of Sir John Evans, 

 for the promotion of agriculture, its object being to report on 

 the methods and results of the Government Agricultural Stations 

 in Canada and other countries, with a view to the establishment 

 of similar institutions in Great Britain. As an unusually large 

 number of papers were read, only those of the most general 

 interest can be here mentioned. 



Prof. Ramsay followed up his address, which was none the 

 less interesting because of its speculative character, by an account 

 of the methods employed in the work on helium and in the 

 determination of the remarkable properties by which that gas is 

 characterised. He expressed the opinion that helium is occluded, 

 and not definitely combined in the various minerals in which it 

 occurs. A short communication was also read, in which it was 

 pointed out by Mr. M. Travers that the hydrogen obtained by 

 heating many igneous rocks iti vacuo is in reality derived from 

 water which is present, and is reduced by various substances, such 

 as ferrous oxide, contained in the material of the rock. 



The section devoted a considerable portion of one of its 

 sittings to the consideration of atomic weights, and was fortunate 

 in the attendance of Profs. B. Brauner, F. W. Clarke, E. W. 

 Morley and T. W. Richards, in addition to the home contingent 

 of chemists distinguished in this particular field. Prof. Brauner, 

 resting from his labours on tellurium, has turned his attention 

 to thorium, and has succeded in making a satisfactory deter- 

 mination of its atomic weight by the oxidation of the double 

 ammonium oxalate. The number which he has obtained is 

 232-5 (0 = i6), and is considerably lower than Cleve's number. 

 Prof. Richards has attacked the problem of the atomic weights 

 of nickel and cobalt, about which great uncertainty has hitherto 

 prevailed, and has analysed the very caretuUy dried and purified 

 bromides of these metals. The separate determinations agree 

 admirably among themselves, and it seems probable that the 



