Abstract
LONDON. Royal Society, March 27.—W. A. Bone, A. R. Pearson, and R. Quarendon: Researches on the chemistry of coal. Part III.—The extraction of coals by benzene under pressure: A new form of apparatus is described for the extraction of coals by means of benzene under pressure up to 700 Ib. per square inch under “Soxhlet “conditions. A large proportion of the benzene extracts from bituminous and sub-bituminous coals (except the Morwell brown coal from Victoria, Australia) always comprises an important group of nitrogenous “humic “bodies, mainly responsible for the coking propensities of bituminous caking coals, of which they constitute 4-5 to 7-0 per cent. The amount of “resins “ordinarily contained in bituminous coals does not exceed I per cent, of the whole coal substance, and they contribute in minor degree only to the coking propensities. The benzene extracts of all the bituminous and sub-bituminous coals examined contain important amounts of neutral wax-like non-nitrogenous bodies, of very low oxygen content, which do not, however, contribute at all to their coking propensities. The residues left after extraction of bituminous coking coals are per se all practically devoid of coking propensities. The extract from the Morwell brown coal consists chiefly of non-nitrogenous unsaponifiable resenes, resene-esters, and aliphatic or alicyclic acids (and esters), of which the last two are highly oxygenated substances.—R. V. Southwell and Sylvia W. Skan: On the stability under shearing forces of a flat elastic strip: The investigation relates to a flat elastic strip, of uniform breadth, thickness, and material, upon which a uniform shear is imposed by tangential tractions applied at its edges and in its plane. These tractions affect both the modes and the frequencies of the free transverse vibrations. If sufficiently intense, they will bring about a condition of limiting elastic stability, since they will neutralise in certain types of distortion the restoring effects of the flexural stresses. Rotatory inertia is neglected. For purposes of comparison, approximate results are obtained by Lord Rayleigh's method, in which the frequency is calculated from the energy equation for a displacement of an assumed type. The correspondence is close, and supplies further confirmation of this method.—J. E. P. Wagstaff: Experiments on the duration of impacts, mainly of bars with rounded ends, in elucidation of the elastic theory: A method depending on duration of discharge of a condenser through a circuit of known resistance and self-inductance has been developed for the accurate determination of duration of collision of steel bars. Variation of time of impact t with initial relative velocity of approach v has thus been studied for a large variety of bars, and a relation of form t =Avy represents the results: y varies with the length I and radius r of the bar according to an equation -1/7=A″+kl/r where A″ and K are constants. The time of impact is not strictly a linear function of length, for short bars, and shows considerable variation with diameter. From results obtained with steel bars, the time of impact for very long bars is extrapolated and compared with the Saint-Venant wave-formula. The result apparently emerges that the pulse, intense and probably largely adiabatic, travels along the bars, about 50 per cent, faster than an isothermal wave. Bars of brass and aluminium are also tested. An extended series of experiments was undertaken with bars of the same cross-section, of unequal lengths, and of masses equalised by loading. Relationships of the form t=Ai were found as before, but they break down for large initial velocities.—E. V. Evans and H. Stanier: Sulphur studies in coal gas. I.—The removal of carbon bisulphide by a nickel catalyst. In removing the sulphur present as carbon bisulphide, the gas is passed over heated nickel. The products are mainly carbon and hydrogen sulphide. In most cases in which nickel is used as a “catalyst in promoting combination with hydrogen, sulphur acts as a poison. The apparently anomalous behaviour of carbon bisulphide is probably due to the fact that the actual catalyst is nickel subsulphide, Ni3S2.—N. Ahmad: Absorption of hard 7-rays by elements. By means of a balance method the absorption in a large number of substances of 7-rays from radium B +C, filtered through i cm. of lead, has been measured. The results indicate that the laws of absorption of these penetrating radiations are of the same type as for X-rays. The apparent atomic absorption (/J.A) can be represented by JBA = i-68 × 10 z + I -60 × 10-314, where z is the atomic number of the absorber. The first term represents the part of absorption due to scattering, the second term that due to “true “absorption. For elements of low atomic weight, the apparent absorption is almost entirely due to scattering, and for those of high atomic weight at least one-half. Estimates of wave-length, based on the two terms in the above formula, lead to values 0-015 and 0-019 A.U. for the mean effective wave-length of the radiation employed.
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Societies and Academies. Nature 113, 513–515 (1924). https://doi.org/10.1038/113513a0
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DOI: https://doi.org/10.1038/113513a0