38: 



NATURE 



[February i6, 1899 



Laubach has suggested, ihat the Medullosea; represent a 

 divergent branch, which has left no descendants among 

 existing vegetation. 



Physical Society, February lo.— Annual General Meeting. 

 — Mr. SheKord Bidwell, F.R.S., I'rcsident, in the chair. — 

 The report of the Council was read by Mr. H. M. Klder. 

 Dr. Atkinson then presented the Treasurer's report, and showed 

 that although there was only a small Vialancc in the bank, the 

 financial position had somewhat improved. The list of Fellows 

 lost to the Society by death was read. After some remarks 

 with regard to the library and the subscriptions, votes of thanks 

 were passed to the Council, the auditors, and to the other officers 

 of the Society. The I'resident then moved a vote of thanks to 

 the Chemical Society for the use of the rooms at Burlington 

 House. Council and officers for the forthcoming year were 

 elected as follows: President, Prof. Oliver J. Lodge, F.R.S. ; 

 vice-presidents who have filled the ottice of president, Dr. J. H. 

 Gladstone, F.R.S., Prof. G. C. Foster, F.R.S., Prof. W. 

 G. Adams, F.R.S., the Lord Kelvin, F.R.S., Prof. R. B. 

 Clifton, F.R.S., Prof. A. W. Reinold, F.R.S., Prof. \V. E. 

 Ayrton, F.R.S., Prof. G. F. Fitzgerald, F.R.S., Prof. 

 A. W. Rucker, F.R.S., Capt. \V. de \V. Abney, C.B., 

 F.R.S., Shelford Bidwell. F.R.S.: vice-presidents, T. H. 

 Blakesley, C. Vernon Boys, F.R.S., (i. Grifiith, Prof. J. 

 Perrj-, F.R.S. ; secretaries, W. Watson (Physical Laboratory, 

 South Kensington) and H. M. Elder (50 City-road, E.C.); 

 foreign secretary. Prof. S. P. Thompson, F.R.S. ; treasurer, 

 Dr. E. Atkinson : librarian, W. Watson. Other members of 

 Council: Prof. H. E. Armstrong, F.R.S., Walter Baily, R. 

 E. Crompton, Prof. J. D. Everett, F.R.S., Prof. A. Gray, 

 F.R.S., E. H. Griffiths, F.R.S., Prof. J. Viriamu Jones, 

 F.R.S., S. Lupton, Prof. G. M. Minchin, F.K.S., and J. 

 Walker. — The newly-elected President, Prof. Oliver Lodge, 

 then took the chair, and an circlinary meeting was held. 

 In his address he referred to the heavy death-roll of 

 the Society during the past year, and to the tribute 

 paid to the memory of John Hopkinson at Cambridge 

 University. Prof Lodge then commented on the ()uick- 

 ness with which scientific discoveries were now applied to 

 practice, and to the interest taken in such applications by men 

 of science. He did not know whether this was due to the 

 example and inspiration of Lord Kelvin, or to the progress of 

 education among the public, lie regretted that the public were 

 so ignorant of scientific subjects. Rapidly reviewing the work 

 done in physics during the past year, he spoke of the experi- 

 ments of Righi, Preston, Michelson, and J. J. Thomson, and I 

 called attention to a prediction, lately published in Nature by 

 Prof G. I''. Fitzgerald, with regard to the probability of being I 

 able to obtain magnetic effects by passing circularly polarised 

 light through absorptive media, .\fter commenting upon the | 

 important position now occupied by terrestrial magnetism among 

 the sciences, and the adv.intages of the publication now known 

 as Science Abstracts, Prof. Lodge said there was one event of 

 exceptional significance to physics, that had happened during 

 the past year, an event of which science would feel the effect 

 for centuries to come — the Government had decided to begin to 

 establish a national laboratory. He wished to congratulate Sir 

 Douglas Gallon, and himself, on the speedy result of their 

 urging the matter ujion the British .Association. He thought 

 the thanks of the Pliysic.al Society wore due to the Committee 

 appointed by the Treasury, especially jierhaps to Prof. Riicker, 

 as acting-chairman of tlut Committee, and to Mr. Chalmers, 

 who represented the Tre.asury, for the way in which the work 

 had been brought to an issue. There was much for which the 

 present Government deserved praise during the p.ast year; he 

 wished there could be added to their laurels the inauguration 

 of a University for London. Pr. if. Lodge then went on to the 

 sjjecific subject of his .address— the opacity of conducting media 

 to light and to electric waves generally, emphasising the brilliant 

 work of Mr. Oliver lleaviside in unifying phenomena ap- 

 parently different, discussing the effect of boundaries, and deal- 

 ing specially with the question, first attacked by Maxwell, of 

 the theoretical op.acity of gold-leaf (This part of the address 

 will be published in full in the J'/iH. Magazine.) Prof. Ayrton 

 said, with regard to the attenuation of electric waves by the 

 earth, that Sir. Whitehead, some months ago, came to 

 the conclusion that when the primary and secondary 

 coils were placed flat on the earth at a distance 

 from one another, nearly all the energy of the primary was 

 absorbed by the earth Iwfore reaching the secondary. The 



NO. 1529, VOL. SQ] 



degree of absorption was so great that Mr. Whitehead had 

 hesitated to publish his theoretical results until experiment 

 should confirm them. Prof. Lodge concurred with Mr. 

 Whitehead's result. Three cases were to be considered. In 

 the first, one horizontal coil is superposed to the other, with 

 sea-water or some other absorbing medium between them ; in 

 this case the absorption at moderate distances is not excessive. 

 But, of course, if the coils are formed of cable sheathed with 

 iron, as in the recent experiments made by the Royal Com- 

 mission, the iron itself prevents the progress of electric waves 

 from primary to secondary. In the second case the coils are 

 wholly in the same horizontal plane. The earth, owing to its 

 great magnitude, behaves almost as a perfect conductor ; if 

 the coils are now near the earth, there is no normal magnetic 

 force between them — it is all tangential. In the third case the 

 coils are oppo.sed to one another, both being vertical, and near 

 to the earth. The high conductivity of the earth is here acting 

 to the advantage of wave propagation, for the image of the 

 primary coil is in phase with the coil itself, and the total elTect 

 is approximately doubled. — Prof. Carey Foster then took the 

 chair, and Prof. Oliver Lodge read a paper by Mr. Benjamin 

 Davies, on a new form of amperemeter and voltmeter with a 

 long scale. These instruments are already well known, although 

 no account of them has actually been puhli^hed. They are of 

 the moving-coil, long-range, portable type, with a very uniform 

 scale from zero to maximum. The magnetic circuit has only 

 one air-gap, which is generally the space between a central 

 cylinder of iron or steel and a concentric tube of iron, modified 

 in various ways for facilitating the adjustment of the magnetic 

 induction and the placing of the coil. The central cylinder is 

 bored axially, and one side of the rectangular coil is pivoted at 

 the top and bottom of the hole thus made. The second side of 

 the coil moves in a circular path in the annular air-gap. 

 Photographs of the instruments in .several modified forms were 

 exhibited. Prof. Ayrton said the instruments appeared to be 

 very successful ; he could bear witness of their value, particularly 

 .as regards the length of range. The general principle by which 

 long-range was to be obtained on moving-coil, portable, in- 

 struments, was developed some ten years ago by NI. Carpentier 

 of Paris, who ussd a central magnet surrounded by a concentric 

 hollow cylinder, with only one side of the coil in the magnetic 

 gap between them ; but it was not then a portable form of 

 instrument, for the coil was suspended. Prof. Ayrton had 

 himself worked in this direction in the "static station-volt- 

 meter," in that instrument there were three magnetic circuits 

 arranged to give staticism ; this was described in 1892 or 1895. 

 — The \'ice- President (Prof. Carey Foster) proposed a vote of 

 thanks to the author, and the meeting adjourned until 

 February 24. 



Chemical Society, February 2.— Prof Dewar, President, 

 in the chair. — The following papers were read : — Maltodextrin, 

 its oxidation products and constitution, by H. T. Brown and 

 J. H. Millar. Pure maltodextrin, isolated from the products 

 of starch hydrolysis, yields, on very careful oxidation, a carboxylic 

 acid which the authors term provisionally maltodextrinic acid 

 A, and to which they assign the constitution 



C,.dL,0„,.O.C,2H5oO„.O.C5lI,0; : 

 this on further oxidation yields a maltodextrinic acid B, 



C,.,H.,,0,„.O.C,H»Oi 

 and maltose. The constitution 



C,sn..,O,„.O.C,jH3„09.0.C„IL,O,„ < , 

 is assigned to maltodextrin, the sign < denoting the open car- 

 bonyl. — On attempts to prepare pure starch derivatives through 

 their nitrates, by 11. T. Brown and J. H. Millar.— The stable 

 dextrin of starch transformations, and its relation to maltodex- 

 trin and to soluble starch, by H. T. Brown and J. H. Millar. 

 A stable dextrin is obtained at an early st.age in the diastatic 

 transforitiation of starch, and yields a carboxylic dextrinic acid 

 on cautious oxidation. The following constitutions are assigned 

 to the dextrin and the dextrinic acid respectively : — 



[ C„H„0,, 

 0„-^{C„H,„OJ„ 

 ( C„ll„Oj< 



f C,H„0. 

 Ojs- (C,3H,„04), 

 I C,II„05 



Propylbenzenesulphonic acids, byG. T. Moody. —The chemistry 

 of the .so-called nitrogen iodide. Part I. The preparation and 

 properties of nitrogen iodide, by F. D. Chattaway and K. J. P. 

 (Jrton. Well-defined crystals of nitrogen iodide are slowly 



