Feb. 20, 1879] 



NATURE 



379 



mistletoe bearing male shoots. The botanists present expressed 

 opinion of its being an androgynous condition rather than a male 

 parasitic on a female plant, as had been supposed. — Mr. R. 

 Irwin Lynch exhibited and made remarks on parts of the Bull's 

 Thorn Acacia {A. spkarocephala), the Imbauba Tree {Cecropia 

 pdtata), and on a couple of Orchids (viz., Espidendron bicornutum, 

 and Schomburghii tibicinus), as exemplifying their economy in 

 affording protection to, and food for, ants. Mr. F. Darwin has 

 already described the two former (Z. S. J. Bot., xv. p. 398), 

 but that orchids should furnish a nidus for ants is apparently a 

 new fact. — A short paper on the position of the genus Sequenzia 

 among the Gasteropoda was read by Dr. J. Gwyn Jeffreys. His 

 opinion differs from that lately promulgated by the Rev. R. B. 

 Watson, believing that it belongs to the Solarium group rather 

 than to the Trochus family, where placed by the latter naturalist. 

 — There followed two papers on the anatomy and on the habits 

 of ants, the gist of which we give elsewhere. 



Physical Society, February 8. — Annual meeting. — The 

 President (Prof. W. G. Adams) read the Report of the Council, 

 which showed that the papers had been more numerous during 

 the past than in any previous year, and that their value and 

 interest had been well sustained. — A copy of the collected 

 papers of the late Sir Charles Wheatstone was laid on the table, 

 and the work wiU shortly be issued to the members of the 

 Society. — The President then gave a brief review of the physical 

 work of the past year, dwelling more especially on the papers 

 read at the meetings. — Votes of thanks were then passed to the 

 president, to the Lords of the Committee of Council on Educa- 

 tion, to the demonstrator, treasurer, secretaries, and auditors, 

 and the following were elected as Council and Officers for the 

 ensuing year : — President — Prof. W. G. Adams. Vice-Presi- 

 sideats— Prof. G. C. Foster, Prof. R. B. Clifton, Lord Ray- 

 leigh. Dr. Spottiswoode, Sir Wm. Thomson. Secretaries — 

 Prof. A. W. ReinoW, Mr. W. Chandler Roberts. Treasurer— Dr. 

 E. Atkinson. Demonstrator — Prof. F. Guthrie. Other Mem- 

 bers ot Council — Capt. W. de W. Abney, Dr. Warren de la 

 Rue, Major E. R. Festing, Prof. Fuller, Dr. Huggins, Prof. A. 

 B. W. Kennedy, Prof. McLeod, The Earl of Rosse, Mr. G. 

 Johnstone Stoney, Dr. Wormell. Honorary Members — Prof. 

 G. R. Kirchhoff, Dr. J. Plateau. — The meeting was then re- 

 solved into an ordinary one, and Dr. O. J. Lodge read a 

 short paper on a method of calculating the course of tem- 

 perature in a rod along which heat is being conducted. — 

 Mr. Shoolbred gave an account of electric lighting illustrated by 

 diagrams of the most recent magneto- and dynamo-electric ma- 

 chines and examples of the lamps in vogue. The only surviving 

 magneto -machine is that of De Meritens, which is incomparably 

 superior to the older ones of NoUet and Holmcc. The dynamo- 

 electric machines described were the continuous-current machines 

 of Siemens, Gramme, Wallace -Farmer, and the alternating 

 current machines of Wilde, Gramme, and Lontin. Wilde's ma- 

 chine is the first of these, or parent machine, and Lontin's so 

 resembles it that the latter cannot be used in England. In these 

 machines the current from a continuous machine is passed through 

 a second machine, which yields the alternating cturents. ; In 

 Lontin's machine also a number of distinct currents are generated 

 in separate circuits, each of which is capable of feeding several 

 lights. There is now one 'in use on the Western Railway of 

 France which gives three distinct currents, each of which suppUes 

 four different lamps, making a total of twelve lights. The 

 American Brush machine was also mentioned. TTie Dubosq 

 lamp, which was the first regulator, is well adapted for labora- 

 t<)ry purposes, but for practical purposes the Serrin is preferable. 

 Rapieff's lamp is used in the Times office. The De Mersanne, 

 which was highly spoken of at the Paris Exhibition, moves the 

 carbons by bevelled gearing. The Wallace-Farmer lamp, though 

 durable, is unsteady, perhaps because only inferior gas carbon has 

 yet been used. Jablochkoff^s candle was foimd to be defective from 

 the solid insulator, such as plaster, used between the carbons. This 

 made it very expensive also. Experiments in Paris had shown that 

 whereas Jablochkoff's system cost \od. per hour per light, the 

 other systems only cost one half of that. In Wilde's candle the 

 solid insulator was dispensed with, air taking its place, the arc 

 always tending to keep at the tip of the candle by electro- 

 d3mamic repulsion. In the De Meritens' candle three strips of 

 carbon were used, the intermediate one being a stepping-stone to 

 the arc, which passes between the two outer ones. Werdermann's 

 and Regnier's so-called incandescent lamps were also shown. 

 Mr. Shoolbred, after alluding to the fact that the upper positive 

 ^rbon takes a crater form, and hence becomes a reflector, 



shedding the light downwards, stated that experiments had 

 proved the line of maximum intensity of light to pass downward 

 at an angle of 60° to the axis of the vertical carbons. By giving 

 the positive carbon a horizontal displacement behind the lower 

 negative one, Mr. Douglass, of the Trinity House, had been able 

 to raise this line till it became horizontal, an advantage in light- 

 houses. He also pointed out that whereas in Paris the 

 Jablochkoff waxed for a period, short compared to that in 

 which it waned, in London it waxed for longer than it waned, 

 which was, of course, an improvement, and Mr. Shool- 

 bred suggested that it might be due to the fact that the engine 

 worked at speed nearer to that of the machine, and that the 

 machine was founded more solidly in London than in Paris. 

 Mr. Werdermann said that it was a mistake to call his lamp an 

 incandescent one, the fact being that all carbon lamps gave light 

 from the incandescence of the positive carbon, and that a small 

 arc was formed in his lamp between the two electrodes, which 

 could be varied by the pressure between them. He maintained 

 that it was as easy to produce 500 lights as 10 from the electric 

 current by subdi\ision, as he hoped soon to show ; and stated 

 that the size of the carbons greatly controlled the intensity of the 

 light. Prof. Ayrton held that the obstacle to the subdivision of 

 the electric light was not an electrical one, but was due to the 

 fact that the amount of light produced by the ciurent is not in 

 direct proportion to the amount of the heat produced. In con- 

 tradiction to Prof. Ayrton, Mr. Werdermann stated that in the 

 electric arc the opposing electromotive force was proportional to 

 the original electro-motive force. Prof. Silvanus P. Thomson 

 pointed out that residual magnetism in the cores of the bobbins 

 of dynamo-electric machines lowered their efficiency, and hence 

 short cores, as in the Wallace-Farmer machine, were an im- 

 provement. 



Edinburgh 



Royal Society, January 20. — Prof. Kelland, president, in 

 the chair. — Prof. Cram Brown gave the third part of a paper by 

 him and J. Adrian Blaikie, B.Sc, on the action of heat on salts 

 of tri-methyl-sulphine. They find that — I. the aqueous solution 

 of tri-methyl-sulphine does not yield crystals when evaporated 

 over sulphuric acid in vacuo, but only a thick syrup was obtained. 

 On heating this at 100° it decomposes — water acetate of methyl 

 and sulphide of methyl being given off. 



CH3-COO-S(CH3)3 = CH3- COO-CH3 ^ (CH8),S. 



II. The aqueous solution of benzoate of tri-methyl-sulphine 

 cystallises in small thin plates which it is difficult to separate 

 from the thick mother-liquor. On heating, the imperfectly dried 

 salt yields at 1 10^ water, siilphide of methyl and benzoate of 

 methyl ; the later boiling at 198°. 



C6H5-COO'S(CH3)3 = CeH5-COO-CH, -t- S(CH3)2. 



III. The dithionate of tri-methyl-sulphine is obtained by neutral- 

 ising free aqueous dithionic acid with the hydrate. It crystallises 

 readily in small clear cubes with one molecule of water of crystal- 

 lisation. It is not hygryscopic. On heating at 220° sulphurous 

 acid begins to come off, and afterwards along with it sulphide ot 

 methyl, leaving methyl-sulphate of tri-methyl-sulphine. 



{(CH3)3S},S206- H20= {(CH3)3SlCH3S04-t- SO, -hS(CH3)j-f- 



^ HjO. ' 



— Prof. Tait then gave the result of some experiments he had 

 been making to determine the electro-motive force of the 

 Gramme magneto-electric machine at different speeds. The 

 exf)eriments were not completed but they seemed to show that 

 the electromotive force varied approximately in the duplicate 

 ratio of the rate of turning. He explained that the Gramme 

 machine with an electromotive power of about 37 Bunsen cells 

 could give as powerful an electric light as a battery of 60 Bunsen 

 cells, for the resistance in the Gramme is very much less 

 than that in the battery of Bunsen. — Prof. Tait gave a 

 note on the law of cooling of bars. He mentioned that in his 

 continuation of the experiments of the late Principal Forbes on 

 the condition of heat in bars, he had been able to reproduce all 

 Forbes's results with one exception. This was that the rate of 

 cooling of the bar when exposed after being heated to ahig i 

 temperature, was found by Forbes to be raAer slower at fii^t 

 than afterwards. Or if we express the temperature of the bar in 

 terms of its excess of temperature above the air, he found that 

 at first it grows till it reaches a maximum and then falls off. 

 Prof. Tait found this phenomenon always at the beginning of his 

 experiments, but by heating the bar to temperatures higher than 

 was required for his experiments, this peculiarity vanished before 



