14 



NATURE 



[May 6, 1920 



approximately simple proportion to distance from 

 the charge. The influence which the water surface 

 exercises on pressure at a given point can be 

 accounted for by supposing that the pressure-wave 

 is reflected from the surface as a tension-wave. The 

 first part of the pressure-wave arrives at the point 

 in question entirely unaffected by proximity of sur- 

 face ; but after a certain interval, determined by the 

 difference in length of direct and reflected paths, the 

 remaining pressure is obliterated by the arrival of 

 the tension-wave. — E. F. Armstrong and T. P. 

 Hilditch : A study of the catalytic action at solid 

 surfaces (iii.). The hydrogenation of acetaldehyde 

 and the dehydrogenation of ethyl alcohol in the 

 presence of finely divided metals. Hydrogenation of 

 Aldehyde. — Aldehyde may be converted into alcohol 

 by passing the vapour together with hydrogen over 

 either copper or nickel (Sabatier) ; but in presence of 

 the latter metal, probably owing to the special affinity 

 of nickel for the carbonyl group, the aldehyde is 

 prone to undergo decomposition into carbon monoxide 

 and methane. Copper at 200-220° effects reduction 

 of aldehyde to alcohol smoothly, but at 300° about 

 50 per cent, of the aldehyde disappears and but little 

 reduction is effected, the recovered aldehyde and 

 alcohol being in about equal amounts. Dehydrogena- 

 tion of Alcohol.— The yield of aldehyde obtained from 

 alcohol as dehydrogenated in the presence of nickel 

 is only 35 per cent., whereas, in the case of copper, 

 not only is the ratio of aldehyde to hydrogen close to 

 that calculated, but the unchanged alcohol may also be 

 recovered almost quantitatively, the yield of aldehyde 

 being about 90-95 per cent, of that to be expected 

 from the amount of alcohol used. There is a striking 

 absence of the secondary products observed when 

 aldehyde together with an excess of hydrogen is 

 passed over the metal at the same temperature. — 

 E. F. Armstrong and T. P. Hilditch : A study of the 

 catalytic action at solid surfaces (iv.). The inter- 

 action of carbon monoxide and steam as conditioned 

 by iron oxide and by copper. It is shown that, like 

 certain forms of iron oxide, prepared copper is able 

 to effect considerable transformation of carbon mon- 

 oxide and steam into carbon dioxide and hydrogen. 

 Whereas, however, iron oxide at a suitable tempera- 

 ture causes the action to proceed almost as far as 

 the equilibrium constant permits, copper does not at 

 its optimum temperature effect more than 50-70 per 

 cent, of the possible amount of chemical change; the 

 exact proportion is to some extent a function of the 

 composition of the original gas employed. The 

 action of copper commences at a little more than 

 200° C, and up to 300° is greater than that of an iron 

 oxide catalyst, the latter being without appreciable 

 effect below 250° C. The difference in behaviour is 

 explained by the hypothesis that copper effects a de- 

 composition of formic acid (momentarily produced 

 '♦^ from carbon monoxide and steam) into carbon dioxide 

 and hydrogen from 190° C. upwards, whereas the 

 iron oxide alternately oxidises carbon monoxide, and 

 is in turn in its reduced form reoxidised by the action 

 of steam. These results are of interest, from the 

 point of view of the general theory of catalysis which 

 the authors have lately put forward, as illustrating the 

 specific action of two different types of catalyst, which 

 produce ultimately the same change (C0 + H20 = 

 COJ + H2), but by an entirely different mechanism, 

 involving production of intermediate systems of quite 

 distinct " kinds.— T. R. Merton : The structure^ of 

 the Balmer series of hydrogen lines. In a previous 

 investigation with Prof. J. W. Nicholson it was found 

 that the separation of the components of the lines 

 Ho and H^S suggested that the series should be 

 regarded as a principal series. It is now found that 

 NO. 2636, VOL. 105] 



the structure of these lines is not invariable, but is 

 altered by the presence of impurities, notably helium, 

 in vacuum tubes containing hydrogen. The optimum 

 conditions of sharpness were found in hydrogen mixed 

 with an excess of helium and cooled to the tempera- 

 ture of liquid air, and under these conditions the 

 separations of the components approximate to those 

 appropriate to a diffuse or sharp series. The appear- 

 ance of the lines in the purest obtainable hydrogen 

 is entirely different. Measurements have been made 

 of the separations of the components under the opti- 

 mum conditions of resolution with the aid of an 

 Echelon diffraction grating, and the physical widths 

 of the lines and the relative intensities of the com- 

 ponents .have been deduced from the measurements. 

 It is suggested that the structure of the lines is com- 

 plex, the relative intensities of the components being 

 variable under different conditions; the structure 

 suggested would appear to be consistent with 

 Sommerfeld's theoretical investigations and with the 

 results of experiment.— H. A. Wilson : Diamagnetism 

 due to free electrons. 



Zoological Society, April 13.— Dr. A. Smith AVood- 

 ward, vice-president, in the chair. — Prof. A. Willey : 

 An apodous Amia calva.—H. A. Baylis and Lt.-Col. 

 Clayton Lane : A revision of the Nematode family 

 Gnathostomidae.— A. M. Altson : The life-history and 

 habits of two parasites of blowflies. * 



Geological Society, April 21.— Mr. R. D. Oldham, 

 president, in the chair.— J. W. D. Robinson: The 

 Devonian of Ferques (Lower Boulonnais). In the 

 Lower Boulonnais, between Calais and Boulogne, 

 lies a small tract of Devonian rocks. They form a 

 link between the Devonian beds in Belgium, France, 

 and Germany, and those of England geographically, 

 and also geologically, since they appear to have been 

 formed in a narrow strait which joined the open seas 

 extending towards the Atlantic and over Germany 

 and Russia.— E. S. Cobbold : The Cambrian Horizons 

 of Comley (Shropshire), and their Brachiopoda, 

 Pteropoda, Gasteropoda, etc. As the study of tht 

 Comley Cambrian fossils proceeded, it became 

 apparent that the several faunas, sketched out in 

 191 1 on the evidence of the trilobites (Q.J.G.S., 

 vol. Ixvii., pp. 282 et seqq.), and their order of 

 appearance may prove to be of more than local 

 interest. The author consequently proposes names 

 for the horizons, ba'sed on their fossil contents, ^ to 

 replace those used in his previous publications, which 

 were often clumsy and only of local origin, though 

 necessary until the fossils were better known. 



Paris. 

 Academy of Sciences, April 12. — M. Henri 

 Deslandres in the chair.— A. Lacroix : The erup- 

 tion of Katla (Iceland) in 1918. This volcano, 

 quiescent since i860, entered in violent eruption 

 in October, 19 18. The eruption was explosive, 

 and there was no lava flow.— G. Bigourdan : 

 The instruments and observations of Bailly at_ the 

 Louvre. The Observatory of the Abbey of Sainte- 

 Genevifeve, at Paris.— E. Aries : The equation of state 

 of ether. The formulae deduced from the equation of 

 state given in earlier communications require modi- 

 fication for ether. The results of the modified formula 

 are compared with Young's experimental figures.— 

 G Julia : Families of functions of several variables.-- 

 L Bianchi : Pairs of surfaces with lines of associated 

 curvature.— C. Camichel : The permanent regime in 

 water-chambers. An account of an experimental study 

 of the water velocities by a photographic method.— 

 C Zenghelis: The action of finelv divided ?as€S--— 

 A Gascard : The melissic alcohol of Brodie. Myncic 



