Sept. 28, 1876] 



NATURE 



499 



rocks in the Iluronian series south of Lake Superior, with re- 

 marks on their abundance, transitions, and geographical distri- 

 bution ; and Mr. Bumham furnishes a seventh catalogue of new 

 double stars. 



Poggendorff^ s Annaletider Physik und Chemie, No. 7, 1876. — 

 We have here the second portion of Dr. Root's inaugural disser- 

 tation on dielectrical polarisation. He finds (i) that there is a 

 dielectrical polarisation which takes less than o'cxxx)82i sec. 

 to be perfectly developed ; (2) that all solid dielectric bodies 

 (sulphur not excepted) show, with continuous discharge or slow 

 commutation, a dielectric reaction which, e.g., in arragonite is 

 perceptible within o '0208 sec, but no longer so beyond 0007 

 sec. ; (3) that in direction and relative size the principal axes of 

 elasticity of Fresnel agree with Maxwell's principal axes of 

 electro- elasticity ; and (4) that only with the aid of Faraday's 

 supposition that a perfect conduction everywhere accompanies 

 polarisation, can the equation K = n^ {i.e., the dielectric per- 

 meability = the square of the index of refraction) be brought into 

 harmony with experience. — A third paper from M. Kohlrausch 

 describes experimental researches on elastic reaction in torsion, 

 expansion, and bending. It relates chiefly to stretching and 

 bending of caoutchouc. The various phenomena are shown to 

 agree with a formula previously given ; and a remarkable result 

 from his study of reaction generally is, that after successive defor- 

 mations of opposite sign, movements of reaction may remain in 

 an electric body, which may pass from one direction into the 

 opposite. —Two methods of determining the indices of refraction 

 of liquids and glass plates are described by M. Wiedemann. — 

 Dr. Vogel communicates observations on ithe spectra of the 

 planets. The light which all of them send us is, he considers, 

 reflected sunlight ; the well-estabUshed fact that there is aqueous 

 vapour in the atmospheres of Jupiter and Saturn makes it im- 

 probable that they have (as has been supposed) so high a tempe- 

 rature as to be self-luminous. The further a planet is from the 

 sun the more marked is the influence of the gaseous envelopes in 

 production of spectroscopic dark bands. — M. von Rath, of Bonn, 

 describes a number of mineralogical specimens, and M. Berthold 

 makes a contribution to the history of the radiometer, to which 

 we shall refer in a separate note. 



SOCIETIES AND ACADEMIES 



London 



Entomological Society, SepL 6, — Mr. J. Jenner Weir, 

 F.L.S., in the chair. Mr. Edward Boscher was elected a 

 member. — Mr. Edward Saunders exhibited some recently- 

 captured specimens of Hymenoptera and Heniiptera, many of 

 them rare in this country, and made some remarks respecting the 

 bug of the house-martin, of which he had taken eighteen speci- 

 mens in the window-sills of a house. — Mr. Weir mentioned 

 that on a recent visit to the South Downs he had suffered much 

 annoyance from the attacks of harvest bugs, as many as eighty 

 pustules appearing on each foot. Sever^ remedies were sug- 

 gested, especially rubbing the affected parts with brandy and 

 water ; but Mr. Smith stated that on one occasion when he was 

 in the Isle of Wight and exposed to their attacks, he was effec- 

 tually relieved from all annoyance by a dose of milk of sulphur. — 

 Prof. Westwood communicated a note with reference to some 

 shoots of horse-chestnut which he had exhibited at the July meet- 

 ing, having been destroyed, apparently, by some Lepidopterous 

 larvae or wood-boring beetles ; but he had smce received from Mr. 

 Stainton some shoots that had been forwarded to him by Sir Thos. 

 Moncrieffe, which had been destroyed by squirrels in precisely 

 the same manner. Sir Thomas had himself seen the squirrels at 

 work splitting the shoots with their teeth and extracting the pith. 

 The Professor also stated that he had received from a cor- 

 respondent in Oxfordshire specimens of the two small species of 

 grasshoppers with long antennae Mecotuma varium. Fab., and 

 Xiphidion clypeatum. Panzer, which he had taken on a pear tree 

 in his garden, where they had been regularly observed for the 

 last five or six years. Mr. McLachlan said that the former 

 insect was frequently observed by Lepidopterists when sugaring 

 for moths. — Mr. Smith communicated the descriptions of three 

 additional species of Fonnicida, from New Zealand, which had 

 been sent to him by Mr. David Sharp since his description of Mr. 

 Wakefield's collection was in the press. Two of the species 

 belonged to genera not previously ascertained, to inhabit New 

 Zealand, namely Amblyopoiu and Ponera. — The following 

 memoirs were read: — "Monograph of the dipterous genus 



Systropus, with notes on the economy of a new species of that 

 genus ; " and " Descriptions of new genera and species of Acro- 

 ceridae." Both were communicated by the President, Prof. 

 Westwood. 



Boston 

 Natural History Society. — During' the Session, 1875-6, 

 Prof. N. S. Shaler has contributed several papers on physical 

 geology, in one of which he attempted to account for the pheno- 

 mena of several areas of glacial erosion. He is persuaded that 

 the melting caused by pressure would put a limit to the accumu- 

 lation of ice at a depth probably not exceeding two miles. This 

 melting would give the ice-sheet a chance to move freely in the 

 direction of least resistance. The flow of the melted water would 

 account for stratification of moraine matter, and for the rounding 

 of pebbles. — Mr. Osten Sacken has revised|the North American 

 species of the Dipteran genus Syrphus. — Dr. W. K. Brooks has 

 made a contribution to the embryology of Salpa, which is start- 

 ling to naturalists, and will be of great importance if confirmed. 

 He says that in tracing back the history of the zooids composing 

 a chain, the egg is present at all periods of growth, of exactly 

 the same size and appearance as at the time of its impregnation. 

 He concludes that the animal, which has no existence, cannot 

 be the parent of the egg which is already fully formed. Thus 

 the explanation is that the solitary salpa is the female, which 

 produces a chain of males by budding, and discharges an egg 

 into the body of each before birth. These eggs are impregnated 

 while the zooids of the chain are very small and sexually imma- 

 ture, and develop into females which give rise to other males in 

 the same way. After the foetus has been discharged from the 

 body of the male, the latter attains its full size, becomes sexually 

 mature, and discharges its spermatic fluid into the water, to gain 

 access to the eggs of other immature chains. This arrangement 

 is compared with other cases, as in cirripeds, arachnids, argo- 

 naut, in which the male is to some extent parasitic on, or supple- 

 mental to, the female. — Mr. T. T. Bouve has further developed 

 his views of the origin of porphyries from metamorphosed con- 

 glomerates. — Dr. Brooks's paper on the affinity of the mollusca 

 and moUuscoida is worthy of note. He concludes that Brachio- 

 pods are derived from Vermes ; and Polyzoa from some 

 primordial Brachiopod. The polyzoan stem gave off the 

 molluscan veliger, from which the true mollusca have origin- 

 ated by several offshoots. The scaphopods appear to be the 

 least specialised. The Lamellibranchs may be derived from one 

 of these offshoots : they probably diverged early from the ances- 

 tral form, becoming degraded in certain respects and specialised 

 in others. The president, Mr. T. T. Bouve, gave a very inter- 

 esting address on March 15, describing the origin and early 

 proceedings of the society, its struggles with difficulties and 

 ignorance, and the stages by which it has reached its present 

 successful position. He stated that the society's museum, as 

 now arranged, constituted a series of lessons in the structure of 

 the earth and its constituent parts, and in the or ganisation of the 

 plants and animals on its surface. Special lectures have been 

 given to teachers, and other efforts have rec ently been made by 

 the society for the spread of science. 



Rome 



R. Accademia dei Lincei, February — April. — The follow- 

 ing, among other papers, were read : — On the common origin 

 of the Marian and Vatican hills, by M. Ponzi. They were 

 formed by a great seismic oscillation which laid bare their 

 entire stratigraphical arrangement The marls at the base 

 of the Vatican hill have yielded many organic remains re- 

 presenting the old sub-Apennine fauna of the upper miocene. 

 — On alkaloids of viscera that have putrefied at a low tem- 

 perature, by M. Selmi. — On the presence of organs of taste in 

 the tongue of Saurians, by M. Todaro. Having indurated 

 several tongues of L. agilis and Z. viridis, made sections, and 

 coloured with picrocaminate of ammonia, he found a large num- 

 ber of gustative organs about the papillae on the lateral margin 

 of the tongue. They are similar in form and arrangement to 

 those in mammals. — On a constant inductor, by M, Volpicelli 

 (appendix to memoir). He had described one of the nature of 

 a Leyden jar. Another consists of a dry pUe, having 10,640 

 pasteboard discs, each covered with sheet -tin on one side and 

 with peroxide of manganese on the other. One pole is coated 

 with a good insulating varnish. The other communicates with 

 the earth. . The dry pile serves usefully in verifying the laws of 

 electric action. — On artificial increase in the tenacity of cotton, 

 by M. Manzoni. — On the inundations of the Tiber at Rome, 



