ii8 



NA TURE 



\jfMne II, 1874 



M. y. Berkeley commented on the injmy done to pears by a 

 species of CiLideviyia and also by a iungwa Uclminthosporinm 

 pyrorum which produced the unsightly crac];ing of the surface. 



Royal Microscopical Society, June 3. — Charles Brooke, 

 F.R.S., pre-ident. in the chair. — Mr. Slack called attention to 

 a slide exhibited under one of the Society's microscopes, as 

 beirga remarkable specimen of Herr Midler's technical skill in 

 diatom mounting. The slide had photographed upon it, in an 

 extremely beautiful and perfect manner, eighty spaces with the 

 names of diatoms below each, and a diatom of corresponding 

 species was mounted in every space. — Mr. Charles Stewart de- 

 scribed and figured on the blackboard the peculiar position of 

 the touch corpusch s in the skin of the hand ; he also exhibited 

 and dt.'cribed a section of an Ascidian, and explained the method 

 of preparation. 



Boston, U.S. 



Society of Natural History, Jan. 7. — Dr. T. Sterry 

 Hunt rtad a paper on the stratification of rock-masses. The 

 crystalline rocks are commonly divided into stratified and 

 iinstrotified. Tiiese two clashes correspond to what the 

 author has designated inHigenous and exotic rocks, but a third 

 class must be distinguished, which he has called endogenous 

 rocks, and which appear to have been deposited from solu- 

 tions, not in open basins, but in fissures at greater or less depths 

 from tt-e surface, and under peculiar conditions of temperature 

 and pressure. To these crystalline deposits belong the various 

 veinstones, including many of the so-called granites, especially 

 those containing the rarer mineral species. The speaker desired 

 to call attention to the fact that a stratiform or layer-like arrange- 

 ment of the constituent parts is often met with, both in exotic 

 and endogenous rocks, and cannot be regarded as characttristic 

 of indigenous rocks, nor as a proof of aqueous deposition at the 

 eartti's surface. While admitting the frequent occurrence of the 

 bended structure in eruptive rock, and the necessity in many 

 cases of a careful gergnostical study to determine to which class 

 a stratiform rork should be referred, the speaker maintained the 

 truly indigenous character of the great formations of gneissic 

 rocks, such as, for example, the Laurentian, which from their 

 wide extent, and from the mode of their association with layers 

 of quartjiie, limestone and iron-oxides, were clearly deposited n 

 hotizontal layers at the earth's surface. 



Feb. 4. — Mr. J. A. Allen read a paper on geographical variation 

 in colour among North American squirrels, exhibiting many speci- 

 mens in illustration of his remarks. The law of geographical varia- 

 tion in size, that representatives of the same species decrease in size 

 with decrease in lat'tude or altitude of their range, was established 

 by Prof. Baird ni 1S57-5S, in respect to both mammals and birds, 

 who also noticed the occurrence of variation with locality in some 

 other respects. Laws have been found to govern these variations as 

 well, and are as follows : — (i) enlargement of peripheral parts 

 towards the southward ; (2) increase in depth, intensity, and 

 extent of dark colours towards the southwards, and (3) increase 

 of colour with increase of hunridity, or the correlation of intensity 

 of colour and the mean annual rainfall. Mr. Allen then proceeded 

 to notice the application of these laws to the family of squirrels. 

 — Prof C. H. Hitchcock spoke of his studies of the Helder- 

 berg racks of New Hamj^shire. lie also described in detail the 

 geology of the northern part of Grafton County, New Hamp- 

 shire, wdiere the Helderberg Rocks can be best studied. 



Paris ' 



" Academy of Sciences, June l. — M. Berti'and in the chair. 

 ■ — M. Jamin presented the following paper iir continuation of his 

 researches on magnetism ; — On the part played by the mean 

 section, the polar surfaces, and the armatures of a magnet. The 

 author concludes that the mean section determines the quantity, 

 and the surface the distribution, of the magnetism. — Presentation 

 of an ingot of 250 kilogrs. of platinum iridium alloy, cast at the 

 Conservatoire des Arts et Metiers, May 13, 1S74, by M. le Gen. 

 Moiin. This enormous ingot is more than i metre in length, 

 and contains about io'3 per cent, of iridium. It was fused in a 

 furnace of limestone by means of an oxyhydrogen blow-pipe 

 vpith seven jet«, the fusion being completed in from 65 to 70 

 minutes. — M. Chevreul communicated a paper containing ob- 

 servations on M. Poussingault's paper on the transformation of 

 iron into steel. — M. Boussingault made son: e remarks in reply, 



and MM. Dumas and Pasteur added some observations. — Ob- 

 servations on the dwarf African races, A propos of the photo- 

 graphs of Akkas sent by Prof. Panceri, by \\. de Quatrefages. 

 — Researches on the simultaneous diffusion of certain salts, by 

 M. C. Marignac. — Probable decrease in the water supply from 

 the Seine basin in the summer and autumn of 1S74, by MM. E. 

 Belgrand and G. Lemoine. The authors predict that the water 

 supply will fall very low from now to the middle of October. 

 — Memoir on the bay of St. Jean de Luz, by M. Bouquet de la 

 Grye. — New process for engraving on copper, by the same 

 author. The plate is first coated with a thin layer of silver, on 

 which is spread a coloured varnish, and the design is then en- 

 graved with a dry point. The tracing is finally etched by a so- 

 lution of ferric chloride. — Note on magnetisrrr, by M. J. M. 

 Gaugain. The present researches relate to the magnetisation of 

 hardened steel. — On the motion of the air in pipes (fourth 

 note), by M. Ch. Bontemps. — On the adulteration of bce's- 

 wax with Japanese wax, by M. Ch. Mene. The author 

 has determined the densities of the pure substances and of mix- 

 lures containing the two kinds of wax in varying proportions. — 

 On the integrals of the differential equations of curves of which 

 the locus of the centres of the intersecting ellipsoids, similar and 

 similarly placed, is a giv'en curve, by M. I'Abbc Aoust. — On a 

 mechanical problem, by M. II. Durrande. — On the principles of 

 correspondence of the plane and of space, by M. Zeuthen. — On 

 the flatness of the planet Mars, by M. Amigues. The author 

 arrives at the conclusion that the planet was formed in two or 

 more stages and that the mean density of the superficial layers 

 is I '54 of the mean density of the nucleus. —On the shock of 

 bodies (second note), by M. G. Darboux. — Perfection of electric 

 chronographs, and researches on electro-magnets, by M. Mircel 

 Deprez. — Study of the products formed by the action of hydro- 

 chloric acid on cast-iron and steel, by M. S. Cloez. The author 

 has separated and made analyses of several hydrocarbons. — On 

 the new triangulation of the Isle of Corsica, by M. F. Perrier. — 

 Of the spectrum of muscle, by M. L. Ranvier. The author has 

 devised an instrument called a viyosptrlroscopc, of which the 

 action depends on the fact that striated muscular fibre when pro- 

 perly prepared acts as a natural diffraction grating. — On certain 

 particulars of the history of casein and albumen .) prcpos of a 

 recent note by M. (ommaille, byM. A. Bechamp. — Experiments 

 which explain the difference of opinion on the constitution of the 

 iron in the blood, by MM. Paguelin and L. Jolly. — On the 

 Tvii\i;lyp/iiis of the vine, by M. A. Fumouze. This Acarus ( T. 

 irhincpKs) is stated by Planchon to destroy Phylloxera, but the 

 author of the present communication does not speak of it hope- 

 fidly as an agent of destruction of the vine scourge. — On a new 

 indigenous genus of terrestrial Lombricians ( Pontodt ilus nitirionis)^ 

 by M. E. Perrier. — On the mode of contagion of cholera, by M. 

 Ch. Pellarin. 



CONTENTS Pack 



MtriiOKOLOGV — Presi^ntand Fliure 9Q 



Recent FRENCrr GEOLoorcAL Works 100 



Our Book Shelf 102 



Letters to the Editur ; — 



The Habits of various Insects. — Fkitz Muller 10 



Kozoun canadcDse— Dr J.W, Dawson, F.R.S. {With lUialuilion) 103 

 Proportionality of Cause and Effect.— British Ql-akteki.v Re- 

 viewer; Robt. B. Havward ; A SENtoR Wkanc;ler : J. 



COLLtER 103 



The Glacial Period.— A. H. Green, F.G.S 105 



Venus's Flv-Trap (.Dwnira miiscipula). By Dr. Burdon Sander- 

 son, F.R.S 103 



Report of Prof. Parker's Huntertan Lectures "On the 

 Structure and Development of the Vertebrate Skull," IV. 



{.iVilh Iltustratwns) 107 



On Spectrum Photography. By J. Norman Lockyer, F.R.S. 



{iVith lUustratiotts) 109 



The Central Pari; of New York and M?. Waterhouse 



Hawkins ,,2 



Eucalyptus globulus rN Mauritius. By Joh.v R. Jackson . . 112 



Coggia's Comet. By J. R Hind, F.R S 113 



Notes 113 



Scientific Serials 115 



Societies AND Academies ,,..ir. 



