July II, 1878] 



NATURE 



295 



index of refraction of the former substance increases in passing 

 from the liquid to the solid state, and it therefore seems im- 

 portant, in connection with the electro-magnetic theory of light, 

 to carefully measure the specific inductive capacity of a con- 

 denser made of wax, as it is cooled through its solidifying 

 point. The rise in capacity, as the temperature falls from 

 80° C. to 60° C, is very striking, and the entire change was 

 found to be in exact agreement with the changes known to occur 

 in the index of refraction for light. An elaborate series of ex- 

 IDeriments was made, which sufficed to show that the results 

 obtained were not due to any change in the distance apart of the 

 plates (of copper) between which the wax was placed, caused by 

 any shrinkage of this wax on solidifying. In consequence of a 

 remark of M. Buff that lead chloride behaves as a metal, Prof. 

 Ayrton has studied it as a dielectric, and he found a diminution 

 of resistance by electrification ; but as this result was not con- 

 firmed on subsequent experiment, the question was more fully 

 investigated, when he found that, with an electromotive force 

 under 175 volts, there is an increase in resistance, and above 

 that amount there is a regular or irregular diminution. This 

 limiting force is about that required to decompose water, and he 

 concludes that the results obtained must be due to the damp 

 contained in the lead chloride. 



Entomological Society, June 5.— H. W. Bates, F.L.S., 

 F.Z.S., president, in the chair. — Mr. J. A. Finzi exhibited a 

 remarkable hermaphrodite specimen of Anthocaris cardamines. 

 — Mr. Rutherford exhibited a series of large cocoons from Mount 

 Camaroons, formed by the larvae of a species of Bombyx allied 

 to Anapha panda, Bdv. These cocoons varied in diameter 

 from four to seven inches, and each one contained from 130 to 

 150 smaller cocoons, all of which were tenanted by a larva or 

 chrysalis in various stages of development. It would appear 

 that Anapka panda, like some other species of Bombycida is 

 social, and that the larvae unite to form an aggregate cocoon of 

 sufficient strength to withstand the attack of enemies and 

 probably extreme changes of temperature.— Mr. Rutherford 

 also exhibited a specimen of a Papilio as a case of so-called 

 "hermaphroditism" with asymmetrical markings on the wings 

 which approached respectively Papilio cynorta and Papilio 

 Boisduvalianus, thus creating an impression that those two forms 

 were but the sexes of one species. These specimens were from the 

 collection of Mr. F. J. Horniman. — Mr. Meldola exhibited photo- 

 graphs of two species of tropical orthoptera sent to Mr. Darvrin by 

 Dr. Zacharias as an illustration of protective resemblance in the 

 very perfect leaf-like appearance • cf the fore-wings ; and some 

 small beetles of the genus \Sper?)iophagiie and their cocoons, 

 which had been found in a packet of seeds of Cassio neglecta, 

 sent from Brazil by Dr. Fritz Miiller to Mr. Darwin. The full- 

 grown larvae had emerged from the seeds, leaving the latter in a 

 damaged condition, and had spun the small cocoons from which 

 the beetles had issued, the insects having reached this country 

 alive. Mr. Meldola also exhibited the proboscis of a sphinx 

 moth caught by the narrow tube-like nectary of a pale yellow 

 Hedychitim, which had likewise been received from Dr. Fritz 

 Miiller, who states that sphinges are frequently found caught in 

 ths manner, — Sir Sydney Saunders communicated notes by 

 Mi. M. Lichtenstein, on new ideas as to the life- cycle of aphi- 

 dians, giving the results of considerable breeding experiments. — 

 The Secretary read a paper from Dr. Fritz Miiller entitled 

 "Notes on Brazilian Entomology, "in which the author gave the 

 results of his observations on the odours emitted by butterflies 

 and moths, as well as facts bearing on various other subjects 

 more or less connected with the theorj' of evolution. In refer- 

 ence to this paper the wings of Aniirrkcea archcea from Brazil, 

 and oiMycalesis drusia horn the Nicobars were exhibited, in 

 illustration of the author's theory of "scent-fans." — The follow- 

 ing papers were also communicated : "On some longicorn 

 Coleoptera from the Hawaiian Islands, " by Dr. Sharp. ' ' On the 

 Larvae of the Tenthredinidae, with Special Reference to Protective 

 Resemblance," by Mr. Peter Cameron ; and " On Macropsebium 

 coterelli, and other New Species of Coleoptera from Lake Nyassa," 

 by Mr. H, W. Bates. The author exhibited the remarkable 

 longicorn beetle above designated, which possessed some 

 prominent characters of the Prionidae, 



Royal Microscopical Society, June 5, 1878.— H. J. 

 Slack, president, in the chair.— Major O'Hara and Dr. j! 

 Edmunds were elected Fellows of the Society. — A paper by 

 Prof. Keith, on the results of a computation relating to 

 ToUes' J-objective, was read by the Seaetary.— Prof. Stokes 



read a paper on the question of a theoretical limit to the 

 apertures of microscopical objectives, in which he showed 

 that, theoretically, a pencil of rays from a radiant in glass (or 

 under equivalent conditions) of 180° could be refracted by a 

 single refraction at a spherical surface, so as to present to the 

 second lens a pencil of about 8i° free from spherical aberration ; 

 and, while not asserting the possibility of utilising the whole of 

 the pencil of 180° in glass, he thought a very large part of it 

 might be available in a practical construction — a far larger part 

 than can be xised with dry lenses. The subject was further dis- 

 cussed by Messrs. Ingpen, Stephenson, and Mayall. — The other 

 papers were on the measurement of the diameter of the 

 flagella of Bacterium termo, by the Rev, W. H, Dallino-er • 

 on the framework of the mastax of Melicerta ringens, by 

 Mr, F. A. Bedwell ; a translation by Mr. Kitton of a paper by 

 M. Petit on some new genera and species of diatoms ; and a 

 note by Mr. J. H. Stephenson on the effect produced on Pleuro- 

 sigma angulatutn by stopping out the central dioptric pencil. 

 Mr. Stephenson exhibited, after the meeting, Pleurosigma angu- 

 latutn, with his new oil-immersion lens, under the conditions 

 explained in his paper; and Mr. Mayall demonstrated the 

 apertiu-e of ToUes' ^-objective, by Abbe's apertometer, to be 

 largely in excess of the maximum possible for dry lenses. Some 

 extremely good slides of the mastax of Melicerta and Cono- 

 chilus, mounted by Lord S, G. Osborne, which had been sent 

 by Mr. Bedwell, were also exhibited. 



Meteorological Society, June 19. — Mr. C. Greaves, F.G.S., 

 president, in the chair. — J. C. Philips and W. S. Rawsonwere 

 elected Fellows. — The following papers were then read : — The 

 climate of Lundy Island, by A. J. H. Crespi, B.A., F.M.S, 

 Lundy Island, from its geographical position, might be ex- 

 pected to have a mild, damp climate, with cool summers and 

 warm winters, and a small diurnal range of temperature, and 

 so, no doubt, it has, although certain local circumstances in 

 addition to its peculiar configuration make the climate remark 

 ably inclement, windy, and unpleasant. The island runs nearly 

 due north and south, having an extreme length of four miles 

 and a breadth of from 200 yards to 1,600 or 1,800; there is 

 a nearly flat table-land or "top" running due north and south, 

 having an altitude of 450 feet; shelter there is none, ever)' 

 current of wind sweeps the whole table-land. From the edge 

 of this table-land the ground slopes away to the sea ; sometimes 

 the descent of the side-land is extremely abrupt, at other spots 

 more gradual, while the side -lands are deeply cut by caves, 

 precipices, small bays, and glens. All around the island the 

 water is deep a few hundred yards cfT, while the currents are 

 formidable, and tremendous seas break upon the rocks almost 

 every day in the year. The one drawback of the place is the 

 wind, so furious and continuous are the blasts first from one 

 quarter, then from another, for days and even weeks. When 

 gales occur, as they generally do at short intervals, the force of 

 the wind becomes incredible : walls are torn down, gates and 

 doors wrenched out of their fastenings, and the few buildings 

 which can be blown down are more or less injured. Fogs are 

 remarkable for their frequency and density, and are nearly 

 always drenching. The rainfall is nearly 50 inches per 

 annum. February and March are said to be the coldest months 

 and August the hottest ; the mean temperature of the year is 

 about 50° or 51°. — On the auroral or magnetic cirrus, by the 

 Rev. S. Barber, F.M.S. —Contributions to the meteorology of 

 Natal, by Dr. R. J. Mann, F.R.A.S. This paper is a discus- 

 sion of the observations taken at Maritzburg (2095 f^^t above 

 sea-level) during the six years 1860-65 ; from it we learn that 

 the summer of Natal is a season of copious rain and the winter 

 a season of relative dryness ; also that the former is a time of 

 abundant and frequent cloud, and the latter a time of prepon- 

 derant sunshine. The summer is consequently cooler in a ma- 

 terial degree than it would otherwise be, on account of the fre- 

 quent prevalence of cloud and the abundance of the rainfall ; and 

 the winter has its temperature materially' raised from the constant 

 occurrence of clear skies and bright sunshine. The mean annual 

 rainfall was 31 '13 inches, [of which amount nearly 28 inches 

 cameTdown during the six summer months (October to March), 

 and scarcely more than 2 inches during the four midwinter 

 months {May to August), Thunderstorms are of frequent oc- 

 currence, the average exceeding seven per month from October 

 to March. The thermometer rarely rises above 85° in the shade 

 even in the summer months, unless a hot wind is blowing ; 

 it then mounts to somewhere between 85° and 97° according to 

 the strength of the sirocco. The degree of humidity indicated 



