April 13, 1893] 



NATURE 



575 



term R was such that C-R represented the whole waste loss in 

 the conductor, whilst A included everything wasted outside the 

 conductor. — A paper on the viscosity of liquids, by Prof. J. 

 Perry, F.R.S., assisted by J. Graham and C. W. Heath, was 

 read by Prof. Perry. The viscosity was tested by suspending 

 a hollow cylinder within an annular trough containing the 

 liquid, and measuring the torque exerted on the cylinder when 

 the trough rotated at various speeds about its axis. In the 

 paper the equation of motion under the conditions of the ex- 

 lieriment is discussed, the error introduced by assuming that 

 the liquid moves in plane layers being shown to be about 05 

 per cent. By measuring the viscous torques exerted with dif- 

 ferent depths of liquid in the trough, the correction for the edge 

 of the suspended cylinder was found to be o "8 cm. On plot- 

 ting the results obtained with sperm oil at difTerent temperatures 

 and constant speed, a discontinuity was noticed about 40°. 

 For a speed of nine revolutions a minute the viscosity (/u) could 

 be very approximately calculated from the formula yn = 206 

 (jd - 4-2)""-® below 40° C. and ;u =: 21 '67 (fl - 4-2) ~^'^^ above 

 40° C, Q being the temperature. Experiments on the change 

 of density of sperm oil with temperature, made by Mr. J. B. 

 Knight, indicated a minimum density about 40°. Subsequent 

 experiments with other samples had not confirmed these ob- 

 servations. The paper contains several tables of the results 

 obtained in various experiments. Those performed at constant 

 temperatures show that for slow speeds the torque is strictly 

 projiortional to speed, but afterwards increases more rapidly, 

 probably owing to the critical speed having been exceeded. 

 After concluding the paper Prof. Perry read a letter he had 

 received from Prof. Osborne Reynolds on the subject, who 

 doubted whether the true critical velocities had been reached 

 in the experiments. In the particular arrangement employed, 

 he would expect no critical velocity in the outer ring of liquid, 

 whilst in the inner ring the motion would be unstable from the 

 first. Mr. Rogers pointed out that experiments which corro- 

 borated those of Prof. Perry had been made by M. Couette and 

 published in Ann. de Chim. et de Phys. [6] xxi. 



Geological Society, March 22.— W. H. Hudleston, F.R.S., 

 President, in the chair. — The following communications were 

 read : — On the jaw of a new carnivorous dinosaur from the 

 Oxford clay of Peterborough, by R. Lydekker. The author 

 describes a fragment of the left side of a lower jaw of a carni- 

 vorous dinosaur from the Oxford clay of Peterborough, in- 

 dicating a new genus and species, which he names Sarcolestes 

 Leedsi. Some remarks were made on this paper by the Presi- 

 dent and Prof. Seeley. — On a mammalian incisor from the 

 Wealden of Hastings, by R. Lydekker. In this paper a small 

 rodent-like tooth from the Wealden of Hastings, belonging to 

 Sir John Evans, K.C.B., is described. It is probably the front 

 tooth of one of the mammalian genera found in the Purbeck 

 Beds, as may be gathered from American specimens. The read- 

 ing of this paper was followed by a discussion, in which the 

 President, Sir John Evans, Mr. C. Dawson, Mr. Oldfield 

 Thomas, Dr. Forsyth-Major, Dr. H. Woodward, and the author 

 took part. — On an intrusion of Muscovite-biotite-gneiss in the 

 south-eastern Highlands, and its accompanying thermo-metamor- 

 phism, by George Barrow, of the Geological Survey. (Com- 

 municated by permission of the Director-General of the 

 Geological Survey.) The area to which this paper refers lies 

 in the north-eastern part of Forfarshire, and is drained by the 

 two Esks. The author first describes the distribution, mode of 

 occurrence, and petrological characters of the intrusive masses. 

 In the north-western portion of the area the intrusive rock is 

 always a gneiss, and occurs in thin tongues which permeate the 

 >urrounding rocks. Towards the south-east these tongues 

 amalgamate and form large masses, in which the foliation is 

 less marked. Moreover, in this direction the large masses are 

 often fringed with pegmatite, especially on their southern and 

 eastern edges. Where the rock is a gneiss, it is composed of 

 oligoclase, muscovite, biotite, and quartz, but contains no 

 microcline. As the gneissose character becomes less marked, 

 the oligoclase diminishes in amount, and microcline begins to 

 appear, especially towards the margins of the masses. In the 

 most south-easterly of these microcline is greatly in excess of 

 oligoclase. The differences in structure and composition of these 

 masses are believed by the author to be due to the straining off 

 of the crystals of earlier consolidation during intrusion under 

 great pressure. The still liquid potash-bearing portion of the 

 magma was squeezed out and forced into every plane of weak- 



NO. 1224, VOL. 47] 



ness in the surrounding rocks ; and that portion of it which 

 contained the highest percentage of potash finally consolidated 

 as pegmatite. Special attention is directed to the distribution 

 of pegmatite. This rock is widely distributed in the Southern 

 Highlands, and cuts across every known system of folding. It 

 is consequently newer than any member of the metamorphic 

 series. The surrounding metamorphic schists are next dealt 

 with. These are remarkable for their highly crystalline con- 

 dition, and also on account of the presence of many minerals 

 known to occur in regions where thermo-metamorphism has 

 taken place. The characters of the more important minerals 

 are described in detail. The rocks of the metamphoric area 

 become less and less crystalline as they are followed towards the 

 Highland border. Three zones, characterised respectively by 

 the minerals sillimanite, cyanite, and staurolite, have been 

 roughly mapped. The more important rocks found in these 

 zones are described in detail, and evidence is given to show that 

 the boundaries between the zones do not in all cases coincide 

 with the strike of the rocks. Thus, a thin bed of quartzite, 

 which retains its character in consequence of the simplicity of 

 its chemical composition, may be followed through all the 

 zones ; whereas the bed adjacent to it is in the outer zone a 

 staurolite-schist, in the intermediate zone a cyanite-gneiss, and 

 near the contact with the igneous rock a coarse sillimanite-gneiss. 

 Evidence is given to show that the original rocks formed a sedi- 

 mentary series. The phenomena are compared with those of 

 other areas where thermo-metamorphism has taken place ; and 

 the conclusion is reached that the diflferences are of degree rather 

 than of kind. The special features of the area in question are 

 attributed to the depth at which the change was produced. The 

 paper is illustrated by a map of the district and a table of original 

 analyses. This paper gave rise to a discussion, in which the 

 president, Prof. Judd, Mr. Rutley, General McMahon, Dr. 

 Hicks, Mr. Marr, Dr. Du Riche Preller, Mr. Teall, and the 

 author took part. 



Zoological Society, March 28. — Sir W. H. Flower, 

 K.C.B., LL.D., F.R.S., President, in the chair. — A report 

 was read, drawn up by Mr. A. Thomson, the Society's head- 

 keeper, on the insects bred in the insect-house during the past 

 season. — A communication was read from Mr. Herbert Druce, 

 giving an account of some new species of Lepidoptera Heterocera, 

 chiefly from Central and South A.merica. — Mr. F. E. Beddard, 

 F.R.S., read a paper on the brain of the African elephant. The 

 author gave reasons for disagreeing with some of the conclusions 

 of Dr. Krueg, but confirmed others. The outline is more like 

 that of the carnivorous than the ungulate brain, but the principal 

 furrows appear to be arranged on a plan characteristic of the 

 elephantidae. — Mr. W. T. Blanford showed that the various 

 names hitherto employed in systematic works for the bird called 

 by Jerdon the Himalayan cuckoo {Cttcitlus himalayanus, 

 C. striattis, and C. intermedius) belonged to other species. He 

 also gave reasons for not adopting S. MUller's C. canoroides, 

 and accepted the term C. sattiratus, Hodgson, as the correct 

 scientific name. — A communication was read from Mr. F. M. 

 Woodward, entitled "Further observations on the genitalia of 

 Briti.'-h earthworms." This paper chiefly dealt with supple- 

 mentary gonads which were found to be much more common 

 than had been supposed ; in one specimen an hermaphrodite 

 gland was discovered in addition to testes and ovaries. 



Entomological Society, March 29. — Henry John Elwes, 

 President, in the chair.— Mr. G. C. Champion exhibited a living 

 specimen of a luminous species of Pyrophorus, which had been 

 found in an orchid house in Dorking. It was supposed to have 

 emerged from the roots of a species of CattUya from Colombia. 

 — Mr. A. H. Jones exhibited living full-grown larvae of 

 Charaxes jasius, found by Mr. Frederic Raine, at Hycres, 

 feeding on Arbutus unedo. — Surgeon-Captain Manders exhi- 

 bited a series of Lyccena theophraslus from Rawal Pindi, show- 

 ing climatal variations, the rainy-season form being of darker 

 coloration, and larger than that occurring in the dry season. 

 The ground colour of the former on the under surface was 

 markedly white with deep black striae ; in the latter form the 

 ground colour was distinctly reddish, and the marking reduced 

 to reddish lines. He said that the latter form had been de- 

 scribed as L. alUratiis.—^lx. S. G. C. Russell exhibited a beau- 

 tiful variety oi Argynnis selene, taken near Fleet, Hants ; two 

 varieties of A. selene from Abbot's Wood, Sussex; typical 

 specimens of A. selene and A. euphrasy ne for comparison ; and 



