December 



D' 



1892] 



NATURE 



165 



I 



To complete the example, take 



V = 100,000 cm. per sec. 

 (beincj about twice the average velocity of the molecules of 

 ordinary air at ordinary temperature) ; and take 



(Trt = g cm., 

 as it might be for an ordinary glass vacuum bulb ; and take 



E = Wins> 

 which may not be very far from the truth. 



With these assumptions, we find, by ( t) and (2) approximately, 

 I per second for the initial rise, and 375° for the final tempera- 

 ture, which are not very unlike the results found in some of 

 Crookes' experiments. 



The pressure of the cathode stream of the velocity and 

 density which we have assumed by way of example is pv'-, or 

 100 dynes per square centimetre, or about 100 milligrams 

 heaviness per square centimetre, which is ample for Crookes' 

 wonderful mechanical results. 



The very moderate velocity of I kilom. per second which 

 we have assumed is much too small to show itself by the optical 

 colour test. The fact that this test has been applied, and that 

 no indication of velocity of the luminous molecules has been 

 found, has, therefore, no validity as an objection against Crookes' 

 doctrine of the cathode stream. 



Chemical Society, November 17. — Sir Henry Roscoe, 

 Vice-President, in the Chair. — The Chairman congratulated the 

 Fellows on the great improvement effected in the Society's 

 rooms by the alterations carried out during the recess An 

 address has been forwarded to the sister society in Berlin on the 

 occasion of the celebration of its twenty-fifth anniversary. A 

 resolution was passed at a meeting of the Council expressing 

 deep regret that, through the death of Dr. Longstaff on Sep- 

 tember 23 last, the Society has lost its senior Fellow and one 

 of its Founders. The following papers were read : — Fluosul- 

 phonic acid, by T. E. Thorpe and vV. Kirman. This paper has 

 been already reported in this volume, page 87. — Note on 

 the interaction of iodine and potassium chlorate, by T. E. 

 Thorpe and G. H. Perry. The reaction which occurs when 

 iodine and potassium chlorate are heated together is usually 

 represented by the equation 3 KC103-fIo=KC104 4- KCI-fKIOj 

 + lC\ + 0.2 ; the authors find, however, that the main reaction 

 consists in a simple interchange of iodine and chlorine thus — 

 2KC103-t-I.2 — 2KI03-hCl2.— The magnetic rotation of sulphuric 

 and nitric acids, and of their aqueous solutions ; also of solutions 

 of sodium sulphate and lithium nitrate, by W. H. Perkin, sen. 

 The author has previously shown that the molecular rotation of 

 sulphuric acid is considerably influenced by the presence of 

 water ; the rotation rapidly falls for small dilutions, but 

 diminishes as the amount of water is increased. The results are 

 now extended ; in the cases of sulphuric acid and sodium sul- 

 phate there is no apparent connection between the values repre- 

 senting the rotation and the extent to which dissociation is sup- 

 posed to occur down to solutions containing 9 per cent, of acid 

 or 12 per cent, of sodium sulphate. At a temperature of 90"" the 

 rotation is increased instead of diminished as indicated by the 

 dissociation hypothesis. The results are not inconsistent with 

 the assumption that the hydrate (HO)4SO is formed. In the 

 case of nitric acid, the curve connecting rotation and percentage 

 of acid is a straight line down to solutions containing 33 per 

 cent, of HNO3, and then apparently bends down somewhat ; 

 the results are not in agreement with the exigencies of the disso- 

 ciation hypothesis. A compound of the composition (H0)3N0 

 may be produced. Lithium nitrate resembles nitric acid m its 

 behaviour. The rotations of strong aqueous solutions of the 

 haloid hydrides change very rapidly with small dilutions, but 

 more slowly with larger dilutions, becoming finally nearly sta- 

 tionary ; such behaviour is not in accord with the dissociation 

 hypothesis, — Note on the refractive indices and magnetic rota- 

 tions of sulphuric acid solutions, by S. U. Pickering. Van der 

 Willingen's results for the refractive indices of sulphuric acid 

 solutions yield curves showing a well-marked "break " at 84'5 

 per cent. (H2SO4 ; H.^O), another "break" at 577 per cent. 

 (H2SO4; 4H2O), and another at 24-30 per cent. The first 

 two of these are also found on the magnetic rotation curves and 

 all three of them agree with breaks found in the examination of 

 other properties. The molecular volumes of solutions of the 

 same strength as those used by Perkin when plotted out exhibit 

 the same three breaks on the curve. — The hydrate theory of 



NO. 1207. VOL. 47] 



solutions. Somi compounds of the .alkylamines with water, by 

 S. U. Pickering. The following table gives the compositions 

 of a number of crystalline hydrates of fatty amines which the 

 author has succeeded in isolating and analyzing : — 



EtNH,,5H20 



PrNH;5H20 



Et2NH,sH..O 



Pr2NH,5H.;0 



MesNH.HoO 



Et3N,2H.,6 



Me3N,3H«0 



EtNHg.S-SHjO 



Bu^NH2,7H20 



Me.,NH,7H,0 



Pr^NH2.8H;0 



PrNH.j,8H20 



Et„NH,8H20 



Me3N,iiH.,0 



The freezing points of the hydrates ranged from + 5° 10-71° ; 

 indications of the existence of other hydrates were also obtained 

 by "breaks" in the curves representing the freezing points of 

 the solutions, and in every instance but one a hydrate 

 of the composition thus indicated in the case of one amine was 

 actually isolated in the crystalline condition in the case of some 

 other amine. In connection with this subject Prof. Thorpe 

 showed a very pretty experiment to illustrate the fact that 

 whilst a mixture of triethylamine (15-50 per cent. ) is clear and 

 transparent at ordinary temperatures, the solution becomes 

 turbid on warming, owing to the amine being thrown out of 

 solution ; on applying pressure to the warm liquid, however, 

 re-solution occurs. — The atomic weight of boron, by E. Aston 

 and W. Kamsay. The authors have investigated the atomic 

 weight of boron ; the atomic weight found from determinations 

 of the water of crystallization of borax is 10921 ±o'oi. The 

 conversion of anhydrous sodium borate into sodium chloride by 

 distilling it with hydrochloric acid and methyl alcohol and 

 weighing the sodium chloride obtained gives an atomic weight 

 of io'966 for boron. The authors consider that Abrahall's 

 number (io'825) for this constant is too low, as the boron 

 bromide employed by him might have been contaminated with 

 the compound BBr3,HBr. — Methoxyamido - i : 3 -dimethyl- 

 benzene and some of its derivatives, by W. R. Hodgkinson and 

 L. Limpach. An almost theoretical yield of I : 2 : 4-metaxyl- 

 enol may be obtained by steam distilling a diazotized 5 per 

 cent, solution of the corresponding xylidine sulphite. The 

 product solidifies in a mixture of solid carbonic anhydride and 

 ether. On nitration a^theoretical yield of a mononitro-derivative 

 {NO2 : OH = I : 2) is obtained. A number of other compounds 

 are described. — An extra meeting of the Society will be held on 

 Tuesday, December 13, at 8 p.m., the anniversary of the 

 death of Stas. A paper by Prof. J. W, Mallet, entitled 

 "Jean Servais Stas, and the measurement of the relative 

 masses of the atoms of the chemical elements " will be read and 

 discussed. 



Physical Society, Nov. 25.— Prof. S. P. Thompson, F.R.S., 

 Vice-President, in the chair. — The followingcommunication was 

 made : Experiments in electric and magnetic fields, constant and 

 varying, by Messrs. Rimington and Wythe Smith. In the first 

 set of experiments shown exhausted electrodcless tubes and 

 bulbs were rotated rapidly in a constant electric field between 

 two parallel charged discs. Double fan-shaped images were 

 produced by the tubes, due to the displacement currents which 

 pass to equalize the potentials at the ends of the tubes. These 

 fans were not symmetrical with respect to the lines of electric 

 force, but were displaced in the direction of rotation. In 

 explanation of this phenomenon it was pointed out that as a 

 tube rotated the potential difference between its ends increased 

 until this difference was sufficient to break down the dielectric 

 in the tube. The discharges would therefore pass at the ends of 

 the intervals during which the difference of potential was rising, 

 and consequently the images would be displaced from the 

 symmetrical position in the direction of rotation. The number 

 of discharges produced during one revolution was found to de- 

 pend on the strength of the electric field, but not on the speed 

 of rotation, and that end of the tube which was approaching the 

 negatively charged plate appeared brightest. These experiments 

 were referred to as examples of the direct conversion of 

 mechanical energy into light. Instead of rotating tubes in a 

 constant electric field, the tubes were next kept stationary, and 

 a varying electric field produced by connecting the plates with 

 an influence machine allowed to spark ; under these conditions 

 the tubes and bulbs were seen to glow. Using large suspended 

 plates charged by an induction coil, long tubes were caused to 

 glow brightly even at considerable distances away from the 

 plates. The glow could be apparently wiped out by passing the 



