July 9, 1891] 



NA TURE 



239 



ends were joined. Dr. Sumpner wished to know how the re- 

 sistances, inductances, and capacities of the circuits and jars 

 were determined, and whether any evidence of irregular dis- 

 tribution of the charges on the tin-foil had been noted. With 

 reference to the overflowing of a jar caused by using a certain 

 length of discharging circuit, he asked whether the overflow did 

 not prove the existence of a higher potential than that which 

 originally existed between the coatings of the jar, and, if so, 

 where did the excess energy come from ? Ur. Thompson asked 

 if it would be possible to make a wire circuit analogous to an 

 open organ-pipe by putting sheets of metal on the ends of the 

 wires. Dr. Lodge, in reply, said Mr. Blakesley's suggestion was 

 an important one, but he had not observed that any change in 

 the adjustment was necessitated by varying the distance between 

 the resonating circuits. Neither had he noticed any glow on 

 wires joined to form a single loop, but this might be possible if 

 the wires were long enough to give harmonics. In answer to 

 Dr. Sumpner he said that the capacities were difficult to deter- 

 mine, for with such rapid oscillations the coatings were virtually 

 enlarged. Lord Rayleigh had shown how to calculate the in- 

 ductances, and the resistances he had practically measured by 

 his alternative path experiments. The overflow of jars he 

 thought was caused by the charges in some way concentrating 

 on the edges of the foil, thus causing a kind of flood tide, at which 

 the overflow occurred. The President asked Dr. Lodge what 

 his views were as to the cause of the opacity of ebonite to light. 

 Was it due to a selective absorption which cut off" only the rays 

 to which the eye was sensitive, or was the ordinary explanation, 

 that it contained impurities which were conducting, and hence 

 acted as screens, likely to be correct ? Another possible ex- 

 planation was that the motion of the ether particles may be in 

 three dimensions, and light be due to the projection of this 

 motion on a plane perpendicular to the ray, whilst electro- 

 magnetic induction might be due to the other component. Dr. 

 Lodge said he believed that ebonite was not opaque because of 

 conducting particles being present, and was inclined to think j 

 that it acted more like ground glass, in which the opacity was 

 due to internal reflections. Such a substance would only be i 

 opaque to vibrations wh ose wave-len gths were comparable with 

 the size of the p articles. i— A nofe^n the construction of non- 

 inductive resistances, by Prof. W. E. Ayrton, F. R. S., and Mr. 

 T. Mather, was postponed until next meeting. 



Zoological Society, June i6. — Dr. St. George Mivart, 

 F.K.S., Vice-President, in the chair.— Mr. H. A. Bryden 

 exhibited an abnormal pair of horns of a cow Eland obtained in 

 the North Kalahari, and made remarks on the structure of the 

 feet of the Lechee Antelope. — Mr. Howard Saunders exhibited 

 and made remarks on a nearly white skin of a Tiger obtained in 

 Northern India by Major D. Robinson. — Mr. Saunders also 

 exhibited specimens of the eggs of a Gull {Lams maculipennis) 

 and of a Tern {Sterna trudeaui) from Argentina. — Mr. Sclater 

 read an extract from a letter received from Dr. Bolau, C.M.Z. S., 

 describing two Sea-Eagles living in the Zoological Garden, 

 Hamburg, and considered to be referable to Steller's Sea- Eagle 

 (Haliactiis pelagictis). One of these, received from Corea, Mr. 

 Sclater pointed out, probably belonged to the species described 

 in the Society's Proceedings by Taczanowski as Haliaclus 

 braitickii. — Dr. R. Bowdler Sharpe gave a short account of the 

 proceedings of the International Ornithological Congress re- 

 cently held at Budapest, in which he had taken part. — Mr. G. 

 A. Boulenger read a paper entitled "A Contribution to our 

 Knowledge of the Races of Rana esctilcnta and their Geographical 

 Distribution." Mr. Boulenger j)roposed to recognize four forms 

 of this widely-spread species of Frog, and pointed out the 

 characters upon which these races were based and the areas 

 which they occupy. — Mr. Oldfield Thomas read some notes on 

 various species of Ungulates, which he had made during a 

 recent examination of the specimens of this group of Mammals 

 in the British Museum. — Mr. Edgar A. Smith gave an account 

 of a large collection of Marine Shells from Aden. To this 

 were added some remarks upon the relationship of the 

 Molluscan Fauna of the Red Sea with that of the Mediter- 

 ranean. — A second communication from Mr. Smith contained 

 descriptions of some hew species of Shells, based on examples 

 obtained durin'g "the ' Challenger Expedition. — Mr. H. A. 

 I'.ryden read some notes on the present distribution of the 



■ iraff^e south of the Zambesi, and made some remarks on the 

 iest mean's of procuring living specimens of this animal for 

 European collections. — A communication was read from Messrs. 

 Mole and Urich containing notes of some of the Reptiles of 



NO. 11 32, VOL. 44] 



Trinidad, of which they had transmitted living examples to the 

 Society's Menagerie. — Mr. F. E. Bed dard read some additional 

 notes upon the anatomy of Hapalemur griseus, made during a 

 recent examination of two specimens of this Lemur. — Mr. E. B. 

 Poulton gave an account of an interesting example of protective 

 mimicry discovered by Mr. W. L. Sclater in British Guiana. 

 This was an immature form of an unknown species of Homopter- 

 ous insect of the family Membracida:, which mimics the Cooshie 

 Ant {CEcodoma cepha'otes). — This meeting closes the present 

 session. The next session (1891-92) will begin in November 

 next. 



Royal Microscopical Society, June 17. — Dr. R. Braith- 

 waite. President, in the chair. — The President said he regretted 

 to announce the death of Prof. P. Martin Duncan, who as a 

 past President of the Society, was well-known to the Fellows. — 

 A negative of Amfhiplcura pellucida, produced with Zeiss's 

 new fV of 16 N. A. and sunlight, by Mr. T. Comber, of 

 Liverpool, was exhibited, and his letter was read suggesting that 

 the want of sharpness was due to the employment of a projec- 

 tion eye-piece for a tube-length of 160 mm., whereas the objective 

 was made for a tube-length of 180 mm. The illumination was 

 axial with a Zeiss achromatic condenser of i*2 N.A. Mr. 

 Comber thought the resolution showed indications of so-called 

 " beading," and he inferred that the ultimate resolution would 

 be similar to that of Amphipleura lindheivteri. The mounting 

 medium had a refractive index of 2*2, but was very unstable, 

 granulations appearing in a very short time. — Mr. C. L. Curlies 

 exhibited Mr. Nelson's apparatus for obtaining monochromatic 

 light. Mr. Mayall said the apparatus was so devised that the 

 microscopist might employ any prism or photographic lens he 

 possessed. If a prism was made specially, one of light crown- 

 glass would probably answer better than the dense flint. — Mr. T. 

 T. Johnson exhibited a new form of student's microscope which 

 he had devised. Mr. Mayall said the special point was the ap- 

 plication of a screw movement to raise and lower the substage, 

 the screw being in the axis of the bearings of the substage 

 and tailpiece ; and the position of the actuating milled head, 

 which projected slightly at the back of the stage, seemed to be 

 most happily chosen. — Dr. J. E. Talmage, of Salt Lake City, 

 Utah, U.S.A., a newly elected Fellow, having been introduced 

 by the President, read a note on the occurrence of life in the 

 Great Salt Lake, and exhibited some specimens of Artemia 

 fertilis from the lake. — Prof. Bell said a paper was read at the 

 February meeting, in which Dr. Benham described a new earth- 

 worm under the name of Eminia equatorialis. The name Eininia 

 having been already given to a bird by Dr. Hartlaub, Dr. Benham 

 proposed tore-name the GdiXihv/orra Eininodrilus. — A letter from 

 Dr. Henri Van Heurck was read, replying to the criticisms of his 

 microscope delivered at the previous meeting. A discussion 

 followed, in which Mr. Mayall, Dr. Dallinger, and Mr. Watson 

 joined. — Mr. T. D. Aldous exhibited the eggs of a water-snail 

 which- were attacked by a parasite which seemed to be destroying 

 the gelatinous matter to get at the eggs. 



Royal Meteorological Society, June 17. — Mr. Baldwin 

 Latham, President, in the chair. — Mr. A. J. Hands gave an 

 account of a curious case of damage by lightning to a church 

 at Needwood, Staffordshire, on April 5, 1891. The church was 

 provided with a lightning-conductor, but Mr. Hands thinks that 

 when the lightning struck the conductor, a spark passed from it 

 to some metal which was close to it, and so caused damage to 

 the building. — Mr. W. Ellis read a paper on the mean tempera- 

 ture of the air at the Royal Observatory, Greenwich, as deduced 

 from the photographic records for the forty years from 1849 to 

 1888, and also gave some account of the way in which, at differ- 

 ent times, Greenwich mean temperatures have been formed. — Mr. 

 Ellis also read a paper on the comparison of thermometrical 

 observations made in a Stevenson screen with corresponding ob- 

 servations made on the revolving stand at the Royal Observatory, 

 Greenwich. From this it appears that the maximum temperature 

 in the Stevenson screen is lower than that of the revolving stand, 

 especially in summer, and the minimum temperature higher, 

 whilst the readings of the dry and wet bulb thermometers on 

 both the screen and the stand, as taken at stated hours, agree 

 very closely together. — Mr. W. F. Stanley exhibited and de- 

 scribed his phonometer, which is really a new form of chrono- 

 graph, designed for the purpose of ascertaining the distance of a 

 gun from observations of the flash and report of its discharge, by 

 the difference of time that light and sound take in reaching the 

 observer. The instrument can also be used for measuring the 

 distance of lightning by timing the interval between the flash 



