May 24, 1888] ££ 



NA TURE 



95 



in absolute measure"; and for substances chemically 

 active, but devoid of Peltier effect, "the E. M.F. is equal to the 

 ynergy of combination of one eleetro-ckemical equivalent." 

 Since metal-metal contacts can only be the seats of Peltier 

 E.M.F.'s it is inferred that the apparent contact E.M.F. 

 [{measured inductively) must be due chiefly to air-metal contacts. 

 jA list of analogous properties of Peltier and chemical E.M.F.'s is 

 biven in parallel columns. The results of some experiments on 

 the contact E.M.F. of glass and ebonite with mercury are 

 [tabulated, but they are very irregular, and the author concludes 

 pat there is no true and definite contact E.M.F. between 

 Conductors and non-conductors. Profs. Ayrton, Schuster, 

 Thompson, and Perry discussed the points raised, and it was 

 considered that direct experiment on contact E.M.F. in a very 

 ct vacuum could alone decide the questions. — On a theory 

 I concerning the sudden loss of magnetic properties of iron and 

 nickel, by Mr. H. Tomlinson. Experiments by himself and 

 other observers have shown that the temperatures at which 

 iron and nickel lose their magnetic properties depend on the 

 specimens used, and the magnetizing forces employed ; but the 

 temperature at which they begin to lose these properties are 

 definite — for nickel about 300° C., and iron about 68o°C. The 

 author's own experiments on " Recalescence of iron " show two 

 critical temperatures ; and Pinchon has shown by calorimetric 

 measurements that between 66o°and 720 C, and between 1000 

 and 1050 C, heat becomes latent. All these facts seem to indicate 

 a molecular rearrangement about these temperatures. In his 

 proposed theory, he assumes that the molecules of iron (say) 

 ontain magnetic atoms capable of motions of translation and of 

 rotation. These tend to form closed magnetic circuits, but at 

 ordinary temperatures are unable to do so on account of the 

 close proximity of their centres. On raising the temperature, 

 their centres are further separated till at about 680° C. their polar 

 extremities rush together, forming complete circuits and exhibiting 

 no external magnetic properties. On cooling down, the centres 

 approach until the gravitation attraction overcomes the magnetic 

 Utraction of their poles, when the magnetic properties reappear. 

 Prof. Ayrton asked whether the author had made experiments 

 on the reappearance of magnetic properties when raised to a 

 white heat, and Prof. Thompson inquired whether cobalt had 

 been tested. Both questions were answered negatively. — Note 

 mi the graphic treatment of the Lamont-Frolich formula for 

 induced magnetism, by Prof. S. P. Thompson. The formula 



Si ' — 



referred to is N = N c , ■ , , ; where N = total induction when 

 Si + b ' 



saturated, N = induction due to Si ampere turns, and b — 

 yalue of Si which makes N = |N. Simple geometrical con. 

 tructions are given for plotting the curve when N and b are 

 cnown, and for finding N and b when two pairs of values of N 

 nd Si have been determined. The use of the formula is shown 

 Iko be justified in practice, for, as pointed out to the author by 

 "'rof. Perry, the curves connecting permeability, fi, and induction, 

 3, are straight lines from B = 7000 to B = 16,000, between 

 vhich dynamos are usually worked. A method of predetermining 

 and b is given for magnetic circuits of known form and 

 aterials, thus removing the objection often urged against the 

 bove formula, viz. that it involves two constants which had to 

 determined after the magnet was made. / 



Mathematical Society, May 10. — Sir/f. Cockle, F.R.S., 

 resident, in the chair. — Mr. E. B. Elliott communicated a 

 ourth paper on cyclicants or ternary reciprocants and allied 

 unctions. — Mr. Cook Wilson gave a sketch of some theorems on 

 •arallel straight lines, together with some attempts to prove 

 Euclid's twelfth axiom. Messrs. Elliott, Buchheim, and Prof. 

 Ienrici, F. R. S., took part in a lengthened discussion of the 

 taper. — The following were taken as read : — On the flexure and 

 he vibrations of a curved bar, by Prof. H. Lamb, F.R. S. — On the 

 igures formed by the intercepts of a system of straight lines in a 

 ilaneand on analogous relations in space of three dimensions, by 

 >. Roberts, F.R.S. — On Lame's differential equation; and 

 (ability of orbits, by Prof. Greenhill. 



Entomological Society, May 2. — Dr. D. Sharp, President, 

 n the chair. — Dr. P. B. Mason exhibited an hermaphrodite speci- 

 nen of Saturnia carpini, from Lincoln, and another specimen of 

 he same species with five wings, bred at Tenby. — Herr Jacoby 



xhibited female specimens of Chrysomelajapana, collected by Mr. 



• II. Leech in Japan, and called attention to a sexual structure in 

 he middle of the abdominal segment. — Mr. Adkin exhibited a 

 •ariety of Eubolia bipunctaria, taken at Box Hill. — Mr. W. F. 



Kirby exhibited, for Dr. Livett, a curious discoloured female 

 specimen of Otnithoptcra mines, Ciamer. — Mr. H. Goss ex- 

 hibited, for Mr. W. Denison-Rcebuck, a rumber of specimens 

 of an exotic species of bee obtained by the Rev. W. Fowler, of 

 Liversedge, from split logwecd. The cells or pouches were very 

 irregular and rough, and altogether unlike those of any known 

 British species.— Dr. J. W. Ellis read a paper entitled "Re- 

 marks on the British Specimens of Aphodius melanostictus, 

 Schmidt," and he exhibited a number of specimens and drawings 

 of this species and of Aphodius ittquinatus, F. A discussion 

 ensued, in which Dr. P. B. Mason, Dr. Sharp, Mr. Champion, and 

 Dr. Ellis took part. — Mr. E. Meyrick communicated a paper on 

 the Pyralidina of the Hawaiian Islands, the material for which 

 paper consisted principally of the collection of Lepidopteia 

 Heterocera formed by the Rev. T. Blackburn during six years' 

 residence in the Hawaiian Islands. Mr. Meyrick pointed out 

 that the exceptional position of these islands renders an accurate 

 knowledge of their fauna a subject of great interest. He stated 

 that, of the fifty-six known species of Hawaiian Pyralidina, nine 

 had probably been introduced through the agency of man in 

 recent times ; but he believed the remaining forty-seven to be 

 wholly endemic : of these latter the author leferred twenty-six 

 species to the Botydidce, twelve to the Scopariada:, four to the 

 Pterophoridie, three to the Cj ambida, and two to the Phycitidw. 

 Dr. Sharp, Mr. McLachlan, Dr. Mason, and Mr. E. B. Poulton 

 took part in the discussion which ensued. 



Paris. 

 Academy of Sciences, May 14. — M. Janssen, President, in 

 the chair. — On diamagnetism, by M. Mascart. In connection 

 with M. Blondlot's recent communication describing an experi- 

 ment on the apparent diamagnetism of a solution of the per- 

 chloride of iron in a more concentrated solution of the same 

 substance, it is pointed out that in 1845 Faraday showed that 

 the action of the magnetic forces on a body depends on the 

 medium in which it is plunged, as it results from the difference 

 of their coefficients of magnetic induction. If the intensity of 

 magnetization remains proportional to the magnetizing force, 

 which is the case with all diamagnetic and slightly magnetic 

 bodies, the theory then shows that the magnetizm on the surface 

 of the body in question changes its sign when the outer medium 

 has a high coefficient. — Remarks accompanying the presentation 

 of a map of Massaya in Abyssinia, by M. d'Abbadie. Attention 

 was drawn to some cartographic improvements introduced into 

 this map by the author with the view of rendering the nomencla- 

 ture more distinct, and more in accordance with the local pro- 

 nunciation of geographical names. In all cases such foreign 

 descriptive terms as Pas, Jebel, &c, give place to their equiva- 

 lents Cape, Mount, Sec. — Fluorescence of cupriferous lime, by M. 

 Lecoq de Boisbaudran. After calcination in the air, carbonate 

 of lime containing a little oxide of copper yields a substances 

 which gives in vacuum an extremely bright green fluorescence. 

 No spectral rays have been observed. When calcination takes 

 place in hydrogen, instead of the green fluorescence, a more or 

 less pink or reddish light is obtained, at times somewhat intense, 

 but always greatly inferior to the green fluorescence. — Observa- 

 tions of the new planet 277, discovered on May 3, at the 

 Observatory of Nice, by M. Charlois. The observations extend 

 over the period from May 3 to May 9, when the planet appeared 

 to be of the thirteenth magnitude.— Observations of the same 

 planet are recorded for the period May 5-12, taken by M. 

 Trepied, at the Observatory of Algiers. — Observations of the 

 channels in Mars, by M. Perrotin. Some important modifica- 

 tions are described, that have taken place in these appearances 

 since they were first observed by the author in 1886. The 

 triangular continent, somewhat larger" than France (the Lybia of 

 Schiaparelli's map), which at that time stretched along both 

 sides of the equator, and which was bounded south and west 

 by a sea, north and east by channels, has disappeared. The 

 place where it stood, as indicated by the reddish-white tint of 

 land, now shows the black, or rather deep blue colour of the 

 seas of Mars. The Lake Mceris, situated on one of the 

 channels, has also vanished, and a new channel, about 20 long 

 and 1° or l°*5 broad, is now visible, running parallel with the 

 equator to the north of the vanished continent. This channel 

 forms a direct continuation of a previously existing double 

 channel, which it now connects with the sea. Another change 

 is the unexpected appearance about the north pole of another 

 passage, which seems to connect two neighbouring seas through 

 the polar ice. — Action of hydrochloric acid on the solubility of 

 stannous chloride ; hydrochlorate of stannous chloride, by M. 



