June 3, 1897] 



NATURE 



119 



such a quantity is the temperature t, at which, for each volume, 

 the substance behaves as a perfect gas. It is shown by tables 

 that T is nearly a constant for volumes from 350 to al)out 8. 

 ISelow volume 8 it diminishes very rapidly with volume. A 

 further investigation refers to the [(a-'^)"'; v'^\ curves of 

 Young, for isopentane, and a corresponding formula. At 

 volume 34 on this curve there is a decided peak, suggesting 

 liscontinuity. Ether gives a similar curve, and the question 

 I ises whether such curves would not be better represented by 

 A o or more equations. Prof. Young said the diagrams repre- 

 >cnting the observed and calculated isothermals were probably 

 the best ever obtained. Divergence among the values of t was 

 explained in part by the smallness of the angle between the 

 theoretical isochor for a perfect gas, and the real isochor. The 

 l^oint of coincidence was difficult to define. Moreover, the 

 values of t were obtained from " unsmoothed " values of v. 

 The evidence against the linear law consisted in a certain 

 similarity in the shape of the different curves. It was not easy 

 M see where experimental errors could come in. The peak 

 IS a very striking feature of the curves, and the agreement 

 I ween the results with ether and those of isopentane was very 

 niarkable. These two substances had their boiling-points 

 close together, their critical temperatures close together, and 

 their molecular weights nearly alike. The two substances not 

 •Illy agreed in each giving a peaked curve, but the peak corre- 

 Mided to almost identical volumes. Prof. Young hoped at 

 me future time to examine normal pentane, and to determine 

 A-ietherr was a constant for this substance also. — The Presi- 

 dent proposed a vote of thanks to the authors of the papers, 

 and the meeting was adjourned until June 11. 



Cambridge. 

 Philosophical Society, April 26. — Mr. F. Daiwm, Pre- 

 sident, in the chair. — On the apparent electrification in an 

 electric field at the bounding surface of two dielectrics, by Prof. 

 A. Anderson. — On luminosity attending the compression of 

 certain rarefied gases, by Mr. H. F. Newall. This paper 

 contains a description of the circumstances under which phos- 

 phorescence has been observed by the author when certain rare- 

 fied gases (initially at a pressure of about 0"oi mm. to 0*05 mm ) 

 are compressed into a volume about one- twentieth of the initial 

 volume. The explanation of the phosphorescence in the case 

 when oxygen is the gas used appears to be in agreement with 

 the explanation- given by Sutherland {Phil. Mag., March 

 1897), of anomalies observed by Bohr and Crookes in the com- 

 pression and rarefaction of this gas. According to Sutherland, 

 in the rarefaction of oxygen a point is reached (pressure 07 

 mm.) when oxygen begins to be converted into ozone, and 

 below the pressure o"i5 mm. the gas is entirely ozone. Between 

 the pressures 1 5 mm. and 07 mm. the gas obeys Boyle's law 



~ oxygen, and below 0*15 mm. it obeys Boyle's law as ozone, 

 tween the pressures 07 mm. and o'i5 mm. the gas is a 



Mixture of oxygen and ozone. Sutherland is led to the view 

 that in the compression of ozone from the lowest pressures, the 

 ozone begins, when the pressure reaches the value o"i5 mm., to 

 be knocked to pieces in virtue of the frequency of collision 

 between ozone molecules being the same as that of some natural 

 vibration in the molecule. It appears that in the phosphor- 

 escence observed by the author as arising during compression of 

 the rarefied gas from a pressure of about 0'02 mm. to pressures 

 lying between 0*3 mm. and 0'5 mm., the ozone is converted 

 into oxygen, and the energy evolved is regarded as resulting in 

 phosphorescence. It is not clear, however, what part is played 

 ih the phenomena by the impurities, but it seems certain that 

 their presence is of importance, if not essential for the pro- 

 duction of the phosphorescence. The spectrum emitted by the 

 phosphorescent gas is very striking, and consists of four bright 

 bands, coinciding with those which Schuster has described as 

 belonging to the spectrum of the negative glow of oxygen. 

 When the same mixture of gas is at a highe ipressure, it is 

 possible to produce in it a bright phosphorescence by passing a 

 momentary electrical discharge through it by Prof. J. J. 

 Thomson's method. The phosphorescence is faint at a 

 pressure of o*6 mm., is at a maximum about 0*4 mm., and is 

 not visible at a pressure below o-i mm. (These pressures vary 

 with the impurities present in the mixture. ) In the electrical 

 production of phosphorescence in oxygen, it would appear 

 (l) that the gas was initially mainly oxygen, (2) that the 

 momentary discharge supplied it quickly with energy and 

 converted it into ozone, and (3) that the ozone slowly reverted 



NO. 1440, VOL. 56] 



again to oxygen with phosphorescence. In this case, however, 

 the spectrum exhibits no bright lines or bands, but is simply 

 continuous. The author offers no explanation of the difference 

 in the spectra in the two cases of phosphorescence, but calls 

 attention to the probable importance of the observation in 

 connection with astronomical matters and, in particular, with 

 the luminosity of extended nebulse. 



Paris. 

 Academy of Sciences, May 24.— M. A. Chatin in the 

 chair. — Tools and weapons of the Copper Age in Egypt : 

 methods and manufacture. New researches, by M. Berthelot. 

 The objects described belong to most ancient Egyptian times, 

 and consist of practically pure copper, no tin being present in 

 any case. A careful examination of some copper needles, found 

 in a tomb at Abydos by M. Amelineau, showed that they had 

 been prepared from a thin lamina of metal, by folding over and 

 subsequent forging. A small chisel obtained from the same place 

 was found to have been made in a very similar manner. A 

 hollow needle was formed from thin copper leaf, in a manner 

 very similar to that employed at the present time in the manu- 

 facture of helical tubing for bicycles. — On some liquids contained 

 in antique vases, by M. Berthelot. A liquid found in a flask 

 near Rheims, probably dating from Roman times, showed that 

 the flask originally contained a fat, into which, the flask being 

 open, water filtered in. — Action on light upon gas mixtures, in 

 case where it causes combination, especially on mixtures of 

 hydrogen and chlorine, by MM. Armand Gautier and H. 

 Helier. No hydrochloric acid is produced from a mixture in 

 equal volumes of hydrogen and chlorine if the latter are pre- 

 pared and kept in the dark. This is the case even after pro- 

 longed exposure, one experiment extending over fifteen months. 

 Similar results were obtained if the mixture was submitted to a 

 very feeble illumination, such as a candle. —New study of tem- 

 pests and tornadoes, by M. H. Faye. Remarks by the author 

 on the presentation of his work to the Academy. — On the stay 

 of General Poncelet at Saratow, by M. Germain Bapst. — New 

 improvement of the grisometer, by M. N. Grehant. The in- 

 strument is placed in a jacket with parallel glass sides, through 

 which water is kept running. — The surface of cast-iron, kept at 

 a red heat, is able to transform carbonic acid into carbon 

 monoxide, by M. N. Grehant. — On the elastic vibra- 

 tion and resistance of cannon, by MM. F. Gossot 

 and R. Liouville. — Scientific mixtures, by M. Constant Dubois. 

 — Remarks by M. Mascart on a catalogue of meteorological 

 observations made in France since 1850, taken from the Annaks 

 du Bureau central miteorologiqiie. — On some doubts cast upon 

 the laws of Colonel Goulier relating to the variations of length 

 of levelling sights, by M Ch. Lallemand. The observations 

 cited, which are mostly produced graphically as curves, all go 

 to confirm the accuracy of the conclusions drawn by Goulier. — 

 On the reflection of light by a long and narrow surface, by M. 

 Gouy. Some remarks on a paper by MM. Nichols and Rubens. 

 — On a phosphorescent anti-anodic system, and the anode rays, 

 by M. C. Maltezos. — On the properties of certain parts of the 

 spectrum, by M. Gustave Le Bon. A reply to the criticisms of 

 M. Becqufcrel concerning the transparency of ebonite for rays of 

 low refrangibility. — On the precipitation of zinc sulphide in 

 the estimation of this metal, by M. J. Meunier. The diffi- 

 culties observed in the precipitation of zinc as sulphide are 

 caused by the presence of a large excess of ammonium 

 sulphide; they disappear if only just sufficient hydrogen 

 sulphide is present to cause the complete precipitation of the 

 zinc— Remarks relating to the heat of formation of the 

 sodium derivatives of acetylene, by M. de Forcrand. Taking 

 into account the latent heat of fusion of acetylene, the latter 

 being deduced from observations by Villard on the heat of 

 formation of the hydrate CjIIj + 6H2O, the amounts of heat 

 developed by the successive replacements of the two hydrogen 

 atoms in acetylene by sodium are very nearly equal, the 

 formation of CoHNa giving out a slightly greater amount 

 (2 Cal.) than that of CjNaj.— Some new combinations of 

 pyridine, quinoline, and piperidine with metallic sails, 

 by M. Raoul Varet. — On the preparation of furfurane, 

 by M. P. Freundler. The dry distillation of barium pyro- 

 niucate gives a poor yield of furfurane, owing to the formation 

 of gaseous products in a secondary reaction ; but a quanti- 

 tative yield is obtained on heating pyromucic acid in small 

 quantities in sealed tubes at 260° to 275 , five grams of the acid 

 giving in this way more furfurane than is obtained by the dry 



