238 



NATURU 



[JVLX 7. 1904 



tinued in its present polytechnic form. Another recommend- 

 ation accepted states, among other points, that, in the event 

 of -its proving impossible to secure the continuance of the 

 Goldsmiths' Institute as a polytechnic, the council would 

 regard it as of great importance to secure its retention 

 as a centre of evening instruction in as many subjects as 

 possible, especially in the higher grades, and to arrange 

 for the continuance of an efficient department of mechanical 

 and electrical engineering for evening students. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, May 9. — "The Fossil Flora of the Culm 

 Measures of North-west Devon, and the Palaeobotanical 

 Evidence with regard to the Age of the Beds." By E. A. 

 Newell Arber. Communicated by Prof. McKenny Hughes, 

 F.R.S. 



The Carboniferous rocks of Devonshire, generally known 

 as the Culm Measures, are divided into an Upper and a 

 Lower division. The Upper Culm Measures, which are of 

 Upper Carboniferous age, form by far the thickest portion 

 of this Carboniferous series. Plant remains, although 

 abundant in these beds, are rarely sufficiently well pre- 

 served to admit of identification. A number of species have, 

 however, been obtained, some of which are new to Britain, 

 from the one horizon in the Upper Culm Measures in which 

 coal, known locally as culm, is found. This flora is 

 identical with that of the Middle Coal Measures elsewhere 

 in England, and consequently the horizon on which the 

 coal or culm occurs in the Bideford district is the equivalent 

 of the Middle Coal Measures, a higher horizon than has 

 been previously assigned to these beds. 



There is also evidence that the Culm Measures at 

 Instow, which occupy a lower horizon than the Culm 

 Measures of the Bideford district, are probably the equiva- 

 lents of the Lower Coal Measures. Thus both the Lower 

 and Middle Coal Measures are represented in Devonshire, 

 and, as the higher beds of the Culm Measures are as yet 

 unexplored, possibly even higher horizons may eventually 

 be found to be represented. 



It is pointed out that the Culm Measures of Devon, which 

 have been regarded by several geologists as essentially a 

 Lower Carboniferous formation, are in reality chiefly, but 

 not entirely, of Upper Carboniferous age. Consequently, 

 the term " culm " or " kulm " generally applied to certain 

 deposits in Germany, Austria, and elsewhere on the 

 Continent, which are entirely of Lower Carboniferous age, 

 is peculiarly unfortunate, for these beds are not of the 

 same age as the great bulk of the Devonshire Culm 

 Measures. 



June 16. — "The Decomposition of .'\mmonia by Heat." 

 By Dr. E. P. Perman and G. A. S. Atkinson. 



Ammonia gas was heated in a porcelain globe placed in 

 a muffle furnace, and the total pressure of the ammonia 

 and decomposition products was read by means of a mercury 

 manometer at equal time intervals, the volume being kept 

 constant. The temperature was measured by a Callendar- 

 Griffiths pvrometer, and was maintained constant within 

 1° or 2° ; in the various experiments it varied from 677° 

 to 1111°. 



At the end of each e.\periment the temperature was 

 raised to about 1100°, and maintained at that point until 

 the decomposition of the ammonia was practically complete ; 

 the pressure was then read again, and from it was calcu- 

 lated the initial pressure of the ammonia in the globe. 



Let p, be the pressure of the ammonia at any instant 

 during the decomposition, /),' that of the nitrogen, p„' that 

 of the hydrogen, P the total pressure at the same instant, 

 p, the initial pressure of the ammonia, then p, + Pi' + pJ = P, 

 p2=3Pi', and pi+pJ = ^{pt~Pi)\ from these equations it 

 follows by substitution that p,=2p„ — 'P, i.e. the pressure 

 of the ammonia at any instant is double the initial pressure 

 minus the total pressure at the instant of observation. The 

 experimental data furnish values of P and 2p„, and values 

 of 2/>„— P have been calculated and tabulated ; from the latter 

 were calculated AP/a/ ; but AP/A( = dP/(/( approximately, 

 and dP/dt = dpJdt, so that the rate of change of pressure 

 of the ammonia at various pressures becomes known. Two 



NO. :8io, VOL. 70] 



scries of curves have been drawn showing the variation of 

 tlis rate with the pressure. The most noteworthy features 

 of the curves are : — (i) at the highest temperatures they 

 become straight lines ; (2) they all run towards the origin i 

 (3) they become much steeper when certain metals 

 (mercury, iron, or platinum) are present in the globe. 

 The chief deductions are : — (i) the decomposition is mono- 

 molecular ; (2) and (practically if not completely) irre- 

 versible ; (3) the rate of decomposition is much increased 

 by the presence of certain metals. 



Some experiments were made also on the effect of sudden 

 change of pressure on the rate of decomposition ; the results 

 confirmed the conclusion that the reaction is monomolecular.' 

 T he irreversibility of the reaction was confirmed by passing 

 nitrogen and hydrogen through a red-hot glass tube con- 

 taining porcelain, when no ammonia was found to be pro- 

 duced. 



Royal Astronomical Society, June 10. — Prof. H. H. 

 Turner, president, in the chair. — Mr. A. R. Hinks read a 

 paper on the reduction of 295 photographs of Eros made 

 at nine observatories during the period 1902 November 7-15, 

 with a determination of the solar parallax ; 110 of the plates 

 were taken at Cambridge, the remainder at Algiers, Lick 

 Observatory, Northfield Observatory, Oxford, Paris, and 

 other observatories. The author described the method em- 

 ploved in the reductions, &c., and gave as the resulting 

 value for the solar parallax 8".7966 + o"oo47, a result nearly 

 in accordance with that obtained by Sir D. Gill from helio- 

 meter observations of minor planets. — Mr. M. E. J. Ghcury 

 read a paper on the gyroscopic collimator of .Admiral 

 Fleuriais. In this instrument the principle of the gyroscope 

 was employed to furnish an artificial horizon for sextant 

 observations at sea. The instrument was shown to the 

 meeting, and its construction and method of employment 

 were described. — Mr. Bryan Cookson gave an account of 

 his paper on the mass of Jupiter, and corrections to the 

 elements of the orbits of the satellites, from heliometer 

 observations made at the Cape Observatory during the years 

 1901 and 1902. , Thq methods of .observation and reduction 

 were explained, and a brief account given of the results. — 

 Mr. E. W. Maunder read a paper on the distribution of 

 sun-spots in heliographic latitude during the years 1874 

 t.-) 1902. The author considered Spoerer's law for the dis- 

 tribution of sun-spots to be true within the limits of its 

 enunciation — that there is only one spot zone in either hemi- 

 sphere except during the brief period just after minimum. 

 — The Rev. .A. L. Cortie read a paper on the variation of 

 latitude of the greater sun-spot disturbances, 1881-1903. 

 Dr. Lockyer briefly replied, contesting some of Mr. 

 Maunder 's conclusions. 



Chemical Society, June 15.— Prof. W. A. Tilden, F.R.S. , 

 president, in the chair. — The following papers were read : — . 

 '1 he mechanical analysis of soils and the composition of the 

 fiactions resulting therefrom : A. D. Hall. The object of 

 the investigation was to ascertain the effect of introducing 

 into the mechanical analysis of soils a preliminary treat- 

 ment of the soil in dilute acid followed by ammonia, as 

 first suggested by Schlcesing. Eighteen soils of knowrr 

 history were selected from the Rothamsted experimental 

 plots, to give comparisons of the same soil in an un- 

 manured condition and when rich in humus through the 

 accumulation of organic matter. With these soils the 

 method involving a preliminary treatment with acid showed 

 the essential identity of soils from the same experimental 

 field whatever the manuring had been, whereas the analyses, 

 made on the raw soil gave very different results, depending 

 on the treatment the various plots had received. — The effect 

 of the long-continued use of sodium nitrate on the constitu- 

 tion of the soil : A. D. Hall. On reviewing the results of 

 the mechanical analysis of the Rothamsted soils, it was 

 observed that those which had been manured with sodium 

 nitrate every year gave abnormal results for the last 

 fraction. The removal of the finest particles from the 

 surface soil is attributed to deflocculation induced by the 

 use of sodium nitrate, and followed by the washing of the- 

 finest particles into the subsoil. — The decomposition of 

 oxalates by heat : A. Scott. It is shown that the decom- 

 position of oxalates by heat is less simple than is generally 

 supposed, and that, except in the case of magnesium oxalate, 

 the oxalates of the common metals generally yield a smali 



