November 7, 1895] 



NATURE 



23 



SCIENTIFIC SERIALS. 



American Journal of Science, October. — Recent progress in 

 optics, by W. Le Conte Stevens. This paper wAs read before 

 the American Association, and gives an admirable summary of 

 Michelson's work with the interferential comparer, of Wiener's 

 experiments with stationary light waves, of recent researches on 

 luminescence, and other subjects. — The quantitative determina- 

 tion of perchlorates, by D. A. Kreider. The method is essen- 

 tially the collection of the oxygen of the perchlorate ; its sub- 

 sequent passage into an atmosphere of nitric oxide over a strong 

 solution of hydriodic acid, and the titration of the iodine thus 

 liberated with decinormal arsenic in alkaline solution. The 

 :ij)paratus employed consisted of a piece of combustion tubing, 

 10 or 12 cm. in length, drawn out at one end and connected 

 with a receiver filled with caustic potash. A platinum boat 

 carried the perchlorate, which was covered with a mixture of 

 sodium and potassium carbonates. The tube was then filled 

 with carbonic acid, and then the oxygen was evolved by fusion. 

 The oxygen was swept by a current of COg into a receiver 

 consisting of two levelling bottles. For the action of the 

 oxygen on hydriodic acid through the medium of nitric oxide, 

 a bulb pipette was used with stopcocks at both ends. This was 

 filled with a known amount of hydriodic acid, and the air ex- 

 pelled by CO2, after which it was exhausted and a small quantity 

 of nitric oxide was admitted. Then the oxygen was allowed to 

 enter slowly under the diminished pressure, while the bulb was 

 constantly shaken. It was then removed for titration, — De- 

 monstration of caustics, by R. W. Wood. A strip of thin 

 polished steel is bent into an arc formed by pins stuck on a 

 board. A piece of cardboard is placed across the opening of 

 the arc, and slits are cut in it about half an inch apart. A 

 piece of photographic sensitive paper is stuck on a board inside 

 the arc. On directing the apparatus towards the sun, parallel 

 rays are traced from the slits to the mirror, and also their re- 

 flections, and the latter form the caustic surface appropriate to 

 the curvature of the mirror. — The law of electromagnetic flux, 

 by M. I. Pupin. The author endeavours to show the exact 

 ]i<)sition which this law occupies in Maxwell's electromagnetic 

 theory ; to point out its limitations ; to show that Maxwell's 

 electromagnetic theory of light demands a more general form of 

 this law ; and to present a general form of this law of which the 

 forms given up to the present are special cases. 



American Meteorological /ournal, October. — Fog signals and 

 meteorology, by Prof. H. Hazen. The author discusses the 

 penetrating power of various signals, the conditions under which 

 fog is formed, and the effects of the winds and topography upon 

 the audibiity of the signals. He considers that, apart from the 

 facts that a sound can be heard about twice as far with the 

 wind as against it, and can be heard farther from an elevation 

 than at the level of the sea, there is hardly a point which is well 

 established. Also that the evidence points very strongly against 

 the use of sirens or trumpets in any but a few exceptional cases 

 where a very long range is demanded. A perplexing difficulty, 

 referred to by the late Prof. Henry, arises from the fact 

 that the signal often seems to be surrounded by a belt, 

 varying in width from one to one and a half miles, from 

 which the sound appears to be entirely absent. He considers 

 that there is urgent need for a series of experiments from a 

 rock or very low island, with open water for ten miles on all 

 Mes. Such experiments would probably elucidate many of the 



iplexing phenomena which now exist. 



SOCIETIES AND ACADEMIES. 



London. 



Entomological Society, October i6.— Prof. Meldola, 



1 . R.S., President, in the chair.— The President announced the 



iths of Prof C. C. Babington, F.R.S., the last but one of the 



-inal members of the Society, and Prof. C. V. Riley, one of 



ten Honorary Fellows of the Society, and commented upon 



air scientific work, Mr. W. F, H, Blandford spoke at some 



iv nt;th on the valuable services rendered by the late Prof, Riley 



■n the cause of economic entomology, and referred to the enor- 



m< .us number of papers and memoirs on the subject which he 



had contributed. Lord Walsingham, F.R.S., also spoke as to 



the importance of the late Prof. Riley's work and the respect 



and regard which he felt for his estimable personal qualities. — 



Mr. F. C. Adams exhibited a series of nineteen Merodon eqties- 



iris, containing several varieties, showing their resemblance to 



NO. 1358, VOL. 53] 



wild bees of the family Apidoe, and made a few remarks on 

 mimicry. He also exhibited specimens of Leptomorphus '..valkeri. 

 Curt., taken in the New Forest in September last, and Melano- 

 stoma hyalinatum, Fin. (male and female), also taken in the 

 New Forest in the latter part of August last. Mr. Verrall, Dr. 

 Sharp, F.R.S., and Colonel Yerbury made some remarks on the 

 species and their distribution. — Mr Enock exhibited, and made 

 remarks on, specimens of the mature male and female, and the 

 nest of Atyptis picetts, the British Trap-door spider ; also male 

 and female specimens of Andrena airicepsa.nd males of A, fulva. 

 — Mr. Tutt exhibited a long series of 143 males and 25 females 

 of Erebia nerine, captured in the Tyrol, partly in the Mendel 

 Pass and partly in the Val d'Ampezza, and read notes on the 

 species, in which he criticised the description of it, and the pub- 

 lished observations as to its habits, by Dr. Lang, Mr. Elwes, and 

 others. Mr. Elwes made some remarks in reply. — Lord Wal- 

 singham exhibited the type of Psetidodoxia limulns (Rghfr. ), 

 together with the larval cases and a preserved larva. He 

 directed attention to the curious truncate concave head of 

 the larva which forms an operculum to the tube, and remarked 

 that the cases of this insect, which were apparently not un- 

 common in Ceylon, the larva feeding on mosses and lichens, 

 had been known for some considerable time. So long ago as 

 1864, Mr. McLachlan found them in the British Museum collec- 

 tion of cases of caddis worms, and at that time, being only 

 acquainted with the case, he was disposed to consider them the 

 work of one of the Leptoceridce. In 1889, Herr Rogenhofer gave 

 the name Ftimea {■) limulus to the case and its contents, and Mr. 

 McLachlan agreed from the evidence then adduced that the 

 insect was Lepidopterous rather than Trichopterous. — Mr. C. J. 

 Gahan exhibited, for Mr. Turner, an imago and some larval 

 forms of Ledra attrita, Linn.— Mr. G. C. Griffiths exhibited, 

 and read notes on, hybrids between Platysamia cecropia (male) 

 and P. gloveri (female), and between P. cecropia (male) and P. 

 ceanotha (female) ; also between Actias Itma (male) and A. selene 

 (female). He stated that these hybrids were bred by Miss 

 Emily L. Morton, of New Windsor, New York, in 1891, 1892 

 and 1893. — Lord Walsingham stated that at the last meeting of 

 the Society some discussion ensued, after the reading of his 

 paper, in consequence of his having alleged that Grapholitha, 

 W., was preoccupied by Grapholitha, Hb. (Verz. Schm.), and 

 he read a supplementary not« on the subject explaining the re- 

 ferences in his iDaper. — Dr. A, G. Butler communicated a paper, 

 entitled " Notes on seasonal dimorphism in certain African butter- 

 flies." 



Paris. 



Academy of Sciences, October 28.— M. Marey in the 

 chair.— The Associates and Correspondents of the Academy are 

 invited to send their photographic portraits to the Secretariat to 

 form part of a projected album.— Lord Kelvin read an address 

 from the Royal Society of London, and then expressed his 

 appreciation of the honour conferred upon him by his election 

 as a Foreign Associate of the Academy. In his speech he 

 referred to France as his Alma mater in science, and mentioned 

 his personal connection with Regnault in 1854 at the College de 

 France.— On the multiple roots of algebraical equations, by M. 

 Brioschi.— On the differences of longitude between Nice, Ajaccio, 

 and Rousse Island, by MM. Hatt, Driencourt, and Perrotin. 

 A telegraphic determination in which observations have been 

 carried out between different pairs of observers, and checked by 

 comparing the longitude of He Rousse determined from Nice 

 with the longitude of the same place determined from Ajaccio, 

 which itself had its longitude compared directly with that of 

 Nice. The direct determination of the difference in longitude 

 of He Rousse and Nice gave 6m. 34'45s- ± o'Cis. Indirect 

 determinations gave 6m. 34 •442s. ± Q-Qigs., and 6m. 34 •465s. ± 

 0-0I7S.— M. Armand Gautier presented the second volume of 

 the second edition of his " Cours de Chimie," and described the 

 points in which it differed from the first edition.— General A. de 

 Tillo presented and described a relief map of the western part of 

 Russia, and the bordering parts of contiguous States.— On 

 chemical equivalents, by M. Marqfoy. The author enunciates 

 the following as a law of chemistry, and supports it by tables 

 printed in the abstract: " The actual equivalents of chemistry 

 are the prime numl)ers comprised in the natural series of whole 

 numbers from i to 300." He adds that he has established the 

 constitutive theory of substances based on the unity of matter. 

 He introduces porosity into the consideration of volumes, and 

 asserts that he thus overthrows Dulong and Petit's law, and 

 Avogadro's hypothesis. The author has found the ft)llowing 



