44B 



NA TURE 



[February i i, 1909 



perplexed scholars, can be explained by comparing' it wilh 

 institutions still surviving amongst primitive peoples ; but 

 it is only of recent years that any such comparison ha^; 

 been made, or such an explanation given. It is not only 

 in the domain of sociology or religion that such a com- 

 parative method is of service. The art of the Greeks, for 

 example, can be shown to have been at one time in a 

 sLage comparable to that of the modern savage, from 

 which it has directly developed. Again, a knowledge of 

 anthropology will be of great service to an intelligent 

 understanding of classical literature. The attacks which 

 have been made on classical studies, and especially on the 

 teaching of Greek, are in great measure due to the classical 

 scholars themselves, who by their pedantry and indiffer- 

 ence to scientific method have caused the reaction which 

 has set in against these studies. 



Mineralogical Society, January 26.— Dr. A. E. H. Tutton, 

 F.R.S., vice-president, in the chair. — The identity of 

 poonahlite with mcsolite : Dr. H. L. Bowman. Small 

 colourless prisms, associated with stilbite and pale green 

 apophyllite from Poonah, which appear to be identical with 

 the mineral described by H. J. Brooke in 1831 as poonah- 

 lite, are shown by analysis to be mesolite, having a com- 

 position corresponding to a mixture of two molecules of 

 scolecite with one of natrolite. The optical characters are 

 similar to those recently observed by Gorgay in mesolite 

 from the Fa;r6e Islands. — Cross-planes in twin-crystals : 

 Dr. J. W. Evans. A twin-plane is composed of two 

 equivalent planes, one from each component crystal, and 

 every line in it is composed of two equivalent lines. A 

 cross-plane is also composed of two equivalent planes, but 

 there are only two, four, or six lines (at right angles in 

 pairs) composed of equivalent lines. \ plane of composi- 

 tion is always a twin-plane or a cross-plane. In the 

 former molecular distances arc the same in all directions 

 in the plane, in the latter in two, four, or six directions 

 only. — Comparison of the refractive indices of adjoining 

 crystals in a rock slice which have their directions of 

 vibration oblique to one another; Dr. J. W. Evans. The 

 N'icols arc placed with their directions of vibration parallel 

 and bisecting the angle B between the directions of the 

 vibrations the refractive indices of which are to be com- 

 pared. The light received from these directions will (apart 

 from interference) be proportional to cos=fl;2, and that 

 from those at right angles to them sin=e/2, so that the 

 former will bear to the latter the ratio cot= 9/2. If 6 be 

 less than 35° this will be greater than ten, and the light 

 from the directions at right angles mav be neglected both 

 in respect of its direct effects on the Becke phenomena and 

 its indirect action in producing interference. — N'ote on the 

 spontaneous crystallisation of solutions as spherulitcs : 

 J. Chevalier. Experiments on solutions of potash-alum, 

 sodium, ammonium and lithium sulphates, &c., made at 

 th<' suggestion of Prof. Miers in the Oxford Mineralogical 

 I-aboratory, show that spherulites and sphero-crystals are 

 characteristic of the spontaneous crystallisation ' of manv 

 solutions in thin drops. When other crystals grow^ first, it 

 is probably because they have been introduced', the drop in 

 that case appearing to be metastable. The spherulites 

 mark the passage of the solution to the labile state.— .A 

 melhod for studying the optical properties of crvstals : the 

 lato Dr. H. C. Sorby. The author gives complete details 

 of his work on the determination of refractive indices in 

 thin plates, of which preliminary accounts have been pub- 

 lished in the first two volumes of the Mineralogical 

 Magazine. The method he describes in the case of doubly 

 refractive minerals is identical in principle (though devised 

 quite independently) with that given by the Due de 

 Chaulnes for singly refractive substances,' but is worked 

 out in far greater detail.— Some additional localities for 

 idocrase in Cornwall : G. Barrow and H. 11. Thomas. 

 fluring the mapping of the metamorphic area round the 

 Bodmin Moor granite, further occurrences of idocrase have 

 l"in found in the altered limestones. Well-shaped crystals 

 of the mineral, up to 6 mm. in length, are fairlv common 

 in drusy cavities. They are perfectly uniaxial, 'but show 

 in thin sections considerable variation in the double re- 

 fraction, especially in the outer lavers of the crvstals. The 

 idocrase is associated with pale' pink to pi'nkish-browm 

 garnet (often in regular intergrowth with the idocrase), 

 xo. 2050, VOL. 7g] 



pale green diopside, and epidote approximating lo clino- 

 zoisite in its low extinction and birefringence. — Detrital 

 andalusite in Tertiary and Post-Tertiary sands : H. H. 

 Thomas. Occurrences of detrital andalusite are described 

 in sands from various localities in West Wales. In no 

 sedimentary rock of greater antiquity than the Pliocene 

 has detrital andalusite been found. In the sands of West 

 Wales the mineral occurs as slightly elongated, somewhat 

 angular grains, often showing very intense pleochroism 

 from blood-red to pale greenish-blue. It is associated in 

 these sands with pink garnet, greenish-brown augite, 

 cyanite, zircon, rutile, tabular anatase, staurolite, brown 

 and more rarely blue tourmaline, green hornblende, bright 

 green epidote, cordierite, iron ores, and in some cases 

 glaucophane. — The energy of twin-crystals : H. Hilton. 

 The author determines in a simple case the conditions 

 according to which a twin-crystal may be a more stable 

 form, or, in otiier words, may have less surface energy 

 than a simple crystal of the same volume. 



'•eological Society, January 27. — Prof. W. J. Sollas, 



I''.R..S., president, in the chair. — The Conway succession : 

 Dr. Gertrude L. Elles. In this area the author found a 

 complete succession of strata, from Llandeilian up to 

 Salopian date. A table of the divisions proposed is given. 

 The beds are described in ascending order, lists of fossils 

 being given from the more important exposures. There is 

 no break in the sequence between the Ordovician and the 

 Silurian rocks in the district. A detailed comparison is 

 established between the rocks of this area and those of 

 South Wales, the Rhayader and Tarannon districts. Lake- 

 land, the south of Scotland, and Pomeroy. The Conway 

 -Mountain volcanic scries appears to be equivalent to the 

 Borrowdale volcanic rocks of the Lake District, and the 

 Cadnant Slates and Bodeidda Mudstones equivalent to the 

 Upper Dicranograptus .Shales, Trinucleus beds, and Sholes- 

 hook Limestone of South Wales, the Sleddale and Roman 

 Fell groups of Lakeland, and the Upper Glenkiln and 

 Lower Hartfell of the south of Scotland. The Deganwy 

 Mudstones are paralleled with the Redhill beds and the 

 Ashgill Shales. Close comparison is possible between the 

 graptolitic zones of the Gyfiin Shales and corresponding 

 beds at Rhayader, Tarannon, in the Lake District, and 

 the south of Scotland. — The depth and succession of the 

 Bovey deposits : A. J. Jukes-Browne. The total thick- 

 ness of the Tertiary beds in the Bovey basin has never 

 yet been ascertained. Some years ago a boring, which 

 reached a depth of 526 feet from the surface, was put 

 down. Particulars concerning the beds traversed by this 

 boring have led to a discussion of the succession of the 

 Bovey deposits, so far as they have been explored. .\ 

 generalised description of the strata seen in the Heathfield 

 pit, and penetrated by the boring from the bottom of that 

 excavation, is given. The conclusion arrived at by 

 Pengclly in 1S61 with regard to the relative age of 

 the beds exposed in the " old coal-pit " south-east of 

 Bovey Tracey, and those proved in a boring to the cast 

 of it, is confirmed. The total thickness of the " Eocene " 

 beds is estimated to be about 613 feet. The Bovey basin 

 itself is regarded as a tectonic basin or post-Eocene peri- 

 cline, and not as a lake-basin. Heer's view of the manner 

 in which the lignites were formed is dissented from, and 

 the' identification of some of the plants discussed, and it 

 is concluded that the lignites, which form the mass of the 

 lower beds, represent the growth and decay of successive 

 swamp-forests. .Assuming these lower beds to be of Eocene 

 age, and contemporaneous with the Bournemouth beds of 

 the Hampshire basin, it is pointed out that nothing has 

 yet been proved with regard to the higher beds, which may 

 be of Bartonian or even of Oligoceno age. 



Maxciiester. 

 Literary and Philosophical Society. Januarv 26. — Prof 

 H. B. Dixon, F.R.S., president, in the cliair. — The dowels 

 of some Egyptian cofiins of the twelfth dynasty : T. G. B. 

 Osborn. An examination was made of various wooden 

 coffins of the twelfth dynasty in the Manchester Museum, 

 using microscopic methods with the view of determining 

 the timber employed in their construction. The wood used 

 in making the body of the coffins was found to be sycamore 

 (Ficus sycomoriis), while the dowels or wooden pins, with 



