434 



NATURE 



[March 4, 1 880 



When the spark was discharged in a magnetic field, known 

 phenomena were reproduced, 'but owing to the thickness and 

 mass of the flame and the extraordinary strength of the magnetic 

 field, they were exhibited in a state of great splendour. 



When the spark passed in an equatorial direction the whole 

 flame was spread out in an equatorial plane, in which heated 

 masses might be seen revolving in one direction or in the other 

 in the neighbourhood of each of the magnetic poles. When the 

 spark passed in an axial direction, or when the poles themselves 

 were made the terminals, the phenomena described in my paper 

 " On an Experiment in Electro-Magnetic Rotation " (Proc. Roy. 

 Soc, March 30, 1S76) were reproduced. 



Whatever » as the direction of the spark, the resistance due to 

 the magnetic field was such as to extinguish the discharge, pro- 

 vided that the striking distance was near the limit that it could 

 attain when no magnetic field was present. If a plate of glass 

 was interposed between the poles of the magnet (which were still 

 used as terminals) the yellow flame disappeared, and the spark 

 divided it-elf into numerous ramifications of true sparks which 

 found their way round the edges of the plate. As soon as the 

 magnet was excited the resistance in the field became so great 

 as to exceed that of the glass plate itself, and the plate was 

 pierced. 



Prof. Dew ar was good enough to measure the efficiency of the 

 secondary discharge, by taking an inch spark in a glass bulb 

 placed in the centre of a calorimeter, in the same way as he had 

 already measured the efficiency of the intermittent current direct 

 from the machine. The former amounted to about 430 gramme- 

 units per minute, while the latter had been found to be 6,000 

 per minute. The relative efficiency may, therefore, be taken at 

 about I : 15. And as the machine was giving about 300 currents 

 per second, this would give for the secondary 



430 : 60 X 300 = '023 units per discharge, 

 and for the primary 



6000 : 60 X 300 = - 3 units per discharge. 



Leaving the subject of the spark from the induction-coil, one 

 of the most remarkable effects produced by this machine was the 

 illumination of vacuum tubes by the currents taken simply from 

 the machine. A small sphere of about two inches in diameter, 

 with an air-vacuum, and having two parallel straight terminals 

 reaching nearly across the sphere and about half an inch apart, 

 was (after the first attempt, when there was some difficulty in 

 getting the discharge to pass) readily illuminated. Owing to the 

 alternate currents, both terminals were of course surrounded with 

 the usual blue halo. When the speed of the machine was 

 reduced, the di-charge through the tube was not maintained, 

 showing that only that part of the current from the machine 

 which pes-essed the highest electromotive force, and perhaps 

 also the greatest strength, was sufficient, and was therefore 

 actually used for the purpose. As this was apparently only a 

 small fraction of the whole current, we may herein find an 

 explanation of the fact that, compared with the effect from the 

 induction spark, the illumination was moderate, and the heating 

 insignificant. It would peihaps not be easy to establish an 

 accurate comparison between this and other sources of electricity ; 

 but some idea may be conveyed by the fact that, from experi- 

 ments made with this tube with Mr. De La Rue's chloride of 

 silver battery on a former occasion, and quite independently of 

 the present question, it was estimated that a current having an 

 electromotive force of 400 volts was necessary to effect a 

 discharge. 



Other tubes were tried, and were illuminated in the same way. 



Chemical Society, February 19.— Mr. Warren De la Rue, 

 president, in the chair.— The list of Officers and Council pro- 

 posed by the Council for the ensuing year was read from the 

 chair. The principal changes are : President : H. E. Roscoe. 

 Vice-Presidents : Warren De la Rue, J. Dewar, V. Harcourt, in 

 the place of 1- . Field and II. E. Roscoe. Other Members of the 

 Council : C. Graham, H. McLeod, E. J. Mills, J. M. Thomson, 

 instead of A. H. Church, W. H. Hartley, and E. Riley, who 

 retire. — During the evening the President mentioned that a 

 crystal had been prepared by Mr. Hannay, of Glasgow ; its 

 angles, lustre, hardness, &c. , were identical with those of the 

 diamond ; a similar crystal when burnt was found to contain 97 

 per cent, of carbon ; it was therefore to all intents and purposes 

 a diamond. — The following papers were read : — On the produc- 

 tion of ozone during the combustion of coal-gas, by R. II. 

 Ridout. The author has observed that a Bunsen burner produces 



ozone, which substance is also formed by the combustion of coal- 

 gas from a glass tube |th of an inch in diameter, placed in the 

 centre of a tube|ths of an inch in diameter and 15 inches long. 

 Ether and alcohol burned from wicks made of capillary glass 

 tubes, gave similar results. — Prof. McLeod then made some 

 remarks in reply to a criticism of Mr. Kingzett as to the forma- 

 tion of ozone during the slow oxidation of phosphorus. In his 

 opinion, while fully admitting the justice of Mr. Kingzett's 

 criticism, the evidence was quite conclusive without the quanti- 

 tative results. He had made about 100 experiments and had n 1 

 been able to find any proof as to the formation of peroxide of 

 hydrogen, whilst the presence of ozone could be always detected. 

 — Mr. R. II. Ridout gave a short account of some new and 

 improved laboratory appliances — a blowpipe for gas or spirit, an 

 india-rubber test-tube brush, an apparatus for saturating a liquid 

 with sulphuretted hydrogen without the slightest escape of that 

 gas, a filter funnel, consisting of a funnel with a stem o'5mm. 

 and the sides ground to the angle of 6o", a continuous aspirator, 

 consisting of a piece of lead tube Jths of an inch in diameter, 

 bent into a circle having a small hole in the concave side, 

 which the aspirating tube is fixed ; a filter funnel in which the 

 vacuum is obtained by the condensation cf steam, and an appa- 

 ratus for taking the gravity of liquids in terms of water at the 

 same or t ther temperatures. — Dr. Armstrong then made some 

 remarks on some recent researches on the so-called unsaturated 

 compounds. 



Zoological Society, February 17. — Arthur Grote, vice- 

 president, in the chair. — Mr. Sclater exhibited and made remarks 

 on a skin of Colobus palliatus, refers, from the Zanzibar Coast, 

 and pointed out its apparent identity with his Colobus angolemis. 

 — A letter was read from Mr. W. B. Pryer, of Elopura, Bay 

 of Sandakan, Noithern Borneo, relating to certain birds and 

 quadrupeds of that country. — Prof. Flower exhibited and made 

 remarks on the skull of a two-horned Rhinoceros (Rhinoceros 

 sumatrti/sis), which had been obtained in Sandakan, Northern 

 Borneo, by Mr. W. B. Pryer. — Mr. Sclater exhibited and made 

 remarks on the drawing of an apparently new parrot, of the 

 genus CJirysotis, now living in the Society's Gardens, which he 

 proposed to call Chrysalis caligena, after Mr. Lawrence's M.S. 

 — Prof. Flower, F.R.S., read a paper on the anatomy of the 

 bush dog (Icticyon vtnaticus), based on a specimen lately, living 

 in the Society's Gardens. — Mr. W. A. Forbes read a paper on 

 some points in the structure of Nasittrna, bearing on its 

 affinities. — A communication was read from Mr. Geoffrey Nevill, 

 C.M.Z.S., containing a paper on the land shells, extinct and 

 living, of the neighbourhood of Mentone (Alpes Maritimes), 

 with descriptions of a new genus and of several new species. — 

 Mr. W. Tegetmeier read a note on the synonymy of the Kaffir 

 Crane, commonly called Balearica regulortim (Licht.). — Lord 

 Walsingham read a paper on some new or little-known species 

 of Tineida:, from North America. 



Royal Microscopical Society, February II. — Anniversary 

 meeting, L)r. Beale, F.R.S., president, in the chair. — Twelve 

 gentlemen were elected or nominated for Fellowship. — The 

 reports of the Council and Treasurer showed that the condition 1 f 

 the Society was highly satisfactory, an exceptionally large number 

 of new Fellows having been elected hist year, and the revenue 

 having increased by more than 200/. A special vote of thanks was 

 given to Mr. Crisp in recognition of his honorary editorship of 

 the journal accompanied by bound copies of vol. i. and ii. with 

 suitable inscriptions. The Officers and Council were tlected for 

 the ensuing year as follows : — President : Lionel S. Bcalc, 

 F.R.S. Vice-Presidents: Robert Braithwaite, M.I'., W. B. 

 Carpenter, C.B., F.R.S. , Prof. P. Martin Duncan, F.R.S. , 

 Henry J. Slack, F.G.S. Treasurer: John Ware Stephenson, 

 F.K.A.S. Secretaries: Charles Stewart, M.R.C.S., Frank 

 Crisp, LL.B., B.A. Members of Council : John Badcock, 

 William A. Bevington, Arthur E. Durham, F. K.C.S., Charles 

 lames Fox, James Glaisher, F. U.S., A. de Souza Guimaraens, 

 "William J. Gray, M.D., John Matthews, M.D., Albert D. 

 Michael, F.L.S., John Millar, L.R.C.P.E., Frederic H. Ward, 

 M.R.C.S., T. Charters White, M.R.C.S.— The President 

 delivered his annual address, in which, after referring to the 

 gratifying position of the Society, and the great improvement 

 that had taken place in the journal, he discussed the nature ot 

 the changes occurring in living matter. Facts and arguments 

 were adduced against the doctrine generally entertained concern- 

 the physical nature of vital phenomena. Many of Dr. Allman's 

 statements in his British Association address were called in 



