February 6, 1908] 



NATURE 



335 



azo type. They also regard Baker's attempt to tormulate 

 these compounds as carbonium salts as unsatisfactory, 

 since it would involve an assumption that p-bromobenzene- 

 azophenol hydrochloride is identical with /)-chlorobenzcnc- 

 azophenol hydrobromide, and they suggest, instead of the 

 formul.'c hitherto proposed, the constitution of oxonium 

 salts for these substances thus, NHPh.N : C^Hj : 0(H or 

 Et)Cl. — A new method of determining vapour densities, 

 part i. : P. Blackman. — Studies in the camphane series, 

 part XXV., action of diazomethane on the two modifica- 

 tions of ijonitrosocamphor : M. O. Forster and H. 

 Holmes. Diazomethane produces with the stable I'so- 

 nitrosocamphor the N-methyl ether, whilst with the un- 

 stable modification isomerisation to the stable variety only 

 takes place. — The oxidation of aromatic hydrazines by 

 metallic oxides, permanganates, and chromates : F. D. 

 Chattaway. Experiments on the oxidation of a number 

 of hydrazines have afforded evidence of the correctness oi 

 the view already put forward by the author that an un- 

 stable hydro.xyhydrazine is first produced, which, in 

 presence of alkalis, breaks down into the hydrocarbon, 

 nitrogen, and water. — Studies in fermentation, part ii., thf 

 mechanism of alcoholic fermentation : A. Slator. .4 

 number of conclusions arc drawn as to the relative veloci 

 ties with which the four principal hexoses are fermented 

 by living yeast, and it is shown that the results can be 

 explained on the assumption that the reaction, which 

 mainly controls the velocity of fermentation, is the de- 

 composition of a stable compound between the enzyme and 

 the sugar. Yeast appears to contain glucozymase, ferment- 

 ing dextrose and Icvulose ; galactozyinase, fermenting 

 galactose; and mannozyniase, fermenting mannose. — 

 Organic derivatives of silicon, part iv., the sulphonation 

 of bcnzylethylpropylsilicyl oxide and of benzylethyldipropyl 

 silicane : H. Marsden and F. S. Kipping. The authors 

 liave prepared benzylethylpropylsilicyl oxide, and find that 

 on sulphonation it furnishes a sulphonic acid identical with 

 that previously resolved into optical isomerides, so thai 

 there can now be no doubt as to the constitution of this 

 substance. — The formation and reactions of imino-com- 

 pounds, part vi., the formation of derivatives of hydrindinp 

 from o-phenylenediacetonitrile : C. W. Moore and J. F. 

 Thorpe. — Valency : J. A. N. Friend. — The esterificntion 

 constants of the normal fatty acids : J. J. Sudborougrh 



and J. M. Gittings. The value E'J _^„ for formic acid 



is 11^4, acetic 104, propionic 92, and from butyric to 

 stearic varies from 50 to 54. — The anomalous behaviour ol 

 the hydrogen electrode in solutions of lead salts and the 

 existence of univalent lead ions in aqueous solutions : 

 H. G. Denham and A. J. Allmand. — Amphoteric metallic 

 hydroxides, part i. : J. K. Wood. — The use of pyridine 

 bases as hydrogen carriers : \V. E. Cross and J. B. 

 Cohen, It is shown that pyridine facilitates the chlorina- 

 tion of benzene and toluene, and the bromination of the 

 same hydrocarbons and of chlorotoluene and naphthalene. 

 — Decomposition of hyponitrous acid : E. Divers. 



Edinburgh. 

 Royal Society, January 20.— Prof. J- C. Ewart, F.R.S., 

 vice-president, in the chair. — The arterial pressure in man, 

 i., methods: Dr. G. .'\. Gibson. A brief historic sketch 

 of the methods used and instruments devised to measure 

 the arterial pressure was followed by a demonstration of 

 Dr. Gibson's own improved form of sphygmomanometer. 

 The records of the pulsations were obtained in the usual 

 way by pointers moving over a smoked surface rolled 

 round a slowly rotating vertical cylinder. To estimate the 

 pressure, the method introduced by Riva-Rocci was 

 adopted. It consisted in compressing the brachial artery 

 above the elbow until the radial artery ceased to beat. 

 The compression bag was connected by flexible tubes wMth 

 a mercury manometer, the pressure value of which was 

 indicated by a float to which one of the recording pointers 

 was attached. The radial pulsation was recorded bv a 

 transmission sphygmograph. .\s the pressure on the radial 

 artery was gradually diminished by opening the valve the 

 oscillations of the mercury began to increase in amplitude, 

 and at a certain point the radial pulsations began to show 

 themselves. The pressure in the mercury manometer, 



NO. 1997, VOL. 77] 



as given by the height of the record above the 

 abscissa at the instant when the radial sphygmograph 

 began to show distinct oscillations, was the measure of the 

 systolic pressure. The gradual diminution in average 

 pressure of the compressing bag as measured by the mano- 

 meter w-as accompanied by an increase in amplitude of the 

 oscillation until a certain average pressure was reached, 

 followed by a decrease until the pressure was the ordinary 

 atmospheric pressure. The lowest point of the maximum 

 oscillation was taken to be the diastolic pressure. The 

 two simultaneous records thus obtained gave all the data 

 at a glance. Interesting e.\amples of records were shown 

 bearing upon various diseases and abnormalities. — Seismic 

 radiations, ii. : Dr. C. G. Knott. On the assumption of 

 a particular law of variation of the speed of propagation 

 of elastic waves with distance from the earth's centre, the 

 forms of the rays and the times of propagation along them 

 were calculated and compared with the results of observa- 

 tion. The conclusion was that the observed facts of the 

 transmission of the preliminary tremors could be co- 

 ordinated on the assumption that throughout all but a 

 comparatively thin crust of the earth the elastic waves of 

 highest speed were transmitted with a speed of 12-23 ^"^^ 

 per second, and that within this crust, of thickness equal 

 to one-tenth the radius, the speed increased from the value 

 6 km. per second at the surface to the value 12-23 at 

 the depth one-tenth of the radius. The second phase of 

 the preliminary tremors was similarly transmitted, but 

 with speed less than that of the first phase in the ratio 

 of 18 to 31-3. The hypothesis that the two phases re- 

 presented the compressional and distortional waves led to 

 the conclusion that the interior of the earth satisfied the 

 uni-constant elastic theory associated with the names of 

 Navier and Poisson. The curving of the rays within the 

 crust of variable speed of propagation led to a concentra- 

 tion of the energy towards the immediate neighbourhood 

 of the epicentre, a result which had important bearings 

 upon the interpretation of seismograms from distant 

 stations. 



Paris. 

 Academy of Sciences. January 27. — M. Henri Becquerel 

 in the chair. — The emission spectra of varieties of fluor- 

 spar : Henri Becquerel. The peculiarities recently pointed 

 out bv A. Dufour in the spectra of fluor-spar as regards 

 the Zeeman effect are probably due to the presence of rare 

 earths in the spar. — Concerning a hitherto unknown frag- 

 ment of the "Opus tertium " of Roger Bacon: P. 

 Duhem. This manuscript. No. 10,264 '" the Bibliothfeque 

 nationale, is headed " Liber tertius Alpetragii." M. 

 Duhem surmises that it is really a portion of the "Opus 

 tertium " of Roger Bacon, and points out that it indicates 

 a clear knowledge of the composition and explosive power 

 of gunpowder before the middle of the thirteenth century. 

 — The geological history and phylogeny of the Anthraco- 

 therideEB : Charles Deperet. — A class of surfaces : M. 



Tzitzeica. — The equation .^-s-=o : Eugenio Elia Levi. 



— The definition of the area of a portion of a curved 

 surface : E. Cartan. The author points out that his note 

 of December 30 last on this subject has been anticipated 

 by M. Schwarz. — The theory of thin bodies : Eugene and 

 Fran(;ois Cosserat. — The action of the X-rays on the 

 photographic plate : M. Chanoz. These experimental 

 results show a parallelism between the successive aspects 

 presented for increasing irradiation by radiographic and 

 photographic negatives. It furnishes an argument in 

 favour of the luminous nature of the X-rays. — The 

 abnormal mobility of the ions of some rare earths : Jules 

 Roux. With the exception of the samarium ion, the 

 mobility of which is of the order of the usual monovalent 

 ions, the mobilities of the other earths studied (lanthanum, 

 yttrium, cerium, and gadolinium) are greater than those 

 of monovalent and divalent ions. This difference may be 

 of use in the separation of these metals, pointing to a 

 possibilitv of effecting their separation by diffusion or by 

 electrolysis. — The radio-activity of the waters at Plom- 

 biferes : Andr^ Brochet. These researches confirm a point 

 already established, that, contrary to a view very commonly 

 expressed, there is no relation between the radio-activit^' 

 of a water and its temperature. — The dissociation by water 



