Dec. 8, 1887] 



NATURE 



M3 



together with the sparsely scattered tests of Foraminifera. The 

 iioximate chemical composition of typical specimens is : — 

 ;a, 50 per cent. ; alumina, 18 per cent. ; limi an,l magnesia, 

 .. ,in 5 to 6 per cent. ; ferric oxide, from 3 to 8 per cent. ; 

 water, 16 per cent., with a small proportion of alkalies, chiefly 

 potash, and but small trace of carbonates. The author's 

 attention was chiefly directed to the common gray friable rocks 

 which may be softened in water and washed on a sieve, the residue 

 consisting mainly of Foraminifera with a few Oitracoda. Of 

 three specimens examined, (i) is a light-gray rojk from close to 

 the sea-level ; (2) of a lighter colour, from about 100 feet 

 elevation ; (3) is nearly white and somewhat harder, and was 

 derived from an intermediate point. So far as the Microzoa 

 are concerned, the first two present no differences which might 

 not be observed in dredgings from the recent sea-bottom, taken 

 at similar depths a litile distance apart. The third appears to 

 have been deposited in so newhat deeper water. There is a 

 marked scarcity of arenaceous Foraminifera. Then followed 

 notes on the rarer and more interesting species, together with a 

 list of the ninety-two species of Foraminifera found. Of these, 

 eighty-seven are forms still living in the neighbourho )d of the 

 Pacific islands. Two of the remaining five are new to science, 

 and the rest extremely rare. The author concluded that these 

 deposits are of Post-Tertiary age, formed at depths of from 150 

 t ^ 200 fathoms in the neighbourhood of a volcanic region. The 

 following new or little-known species were selected for 

 illustration :—^////^(?/(//«<z ellipsoidcs, var. ohlonga, Seguenza ; 

 Haplophraginium rugosum, D'Orb. ; Ehrenhergina biconiis, 

 nov. ; Sphivroidina ornata, nov. The President hoped that 

 this paper might be regarded as one of the first-fruits of travels 

 undertaken by the author for the purpose of investigating the 

 interesting deposits of this nature. Prof. Rupert Jones agreed 

 that this was a valuable instalment of work to be expected. The 

 peculiar Foramlnifer specially mentioned by Mr. Brady 

 (Ellipsndina ellipsoides, var. oblonga, Seguenza) must have 

 connections, so that, as the author has intimated, the interest 

 attached to it was not yet wholly worked out. — On some results 

 of pressure and of intrusive granite in stratified Palaeozoic rocks 

 near Morlaix, in Brittany, by Prof T. G. Bonney, F. R.S. — On 

 the position of the Obermittweida conglomerate, by Prof. T. 

 McK. Hughes. — On the Obermittweida conglomerate : its com- 

 position and alteration, by Prof T. G. Bonney, F. R.S. — Notes 

 on a part of the Huronian series in the neighbourhood of 

 Sudbury (Canada), by Prof. T. G. Bonney, F.R.S. The 

 specimens noticed by the author were in part collected by him 

 in the summer of 1884, when the Canada Pacific Railway was 

 in process of construction, and in part subsequently supplied to 

 him by the kindness of Dr. Selwyn, Director-General of the 

 Geological Survey of Canada. The eastern edge of the district 

 assigned to the Huronian consists of rocks, which may possibly 

 be part of the Laurentian series modified by pressure. But 

 after crossing a belt of these, barely a mile wide, there is no 

 further room for doubt. All the rocks for many miles are 

 distinctly fragmental, except certain intrusive diabases or diorites. 

 These fragmental rocks "are grits, conglomerates, and breccias, 

 which are described as far as about two miles west of Sudbury. 

 The included fragments in these rocks appear to have undergone 

 .some alterations subsequent to consolidation : these are described. 

 In some ca^es the changes appear to be anterior to the formation 

 of the fragments. The matrix also has undergone some change, 

 chiefly the enlargement of quartz grains, and the development 

 or completion of mica-flakes, as in the Obermittweida rock. The 

 author gave some notes on other specimens collected by him 

 along the railway, further west, and on those supplied to him 

 from near Lake Huron by Dr. Selwyn. As a rule these are but 

 little altered. Some contain fragments of igneous rocks, appar- 

 ently lavas. The author discusses the significance of the changes 

 in these rocks, as bearing on general questions of metamorphism, 

 and states that, in his opinion, the name Huronian, at present, 

 includes either a series of such great thickness that the lower 

 beds are more highly altered than the higher, or else tsvo distinct 

 series ; and he inclines to the latter view. Both, however, must 

 be separated from the Laurentian by a great interval of time, 

 and neither exhibits metamorphism comparable with that of a 

 series of schists and gneisses, like the so-called Montalban. The 

 newer reminds him often of the English Pebidians. After the 

 reading of this paper there was a discussion, in which the 

 President, Dr. Geikie, Mr. Rutley, and others took part. 



Royal Meteorological Society, November 16. — Mr. W. 

 £llis, President, in the chair. — The following papers were read : 



— The use of the spectroscope as a hygrometer simplified and 

 explained, by Mr. F. W. Cory. The object of this paper is to 

 suggest as simple a way as possible of using the spectroscope as 

 a hygrometer in order to facilitate its introduction amongst 

 observers as a standard meteorological instrument. The best 

 form of hygro-spectroscope as a recognized standard for the pur- 

 pose of investigating and scrutinizing the changes of the three 

 parts of the spectrum mentioned is that originally termed by Mr. 

 Rand Capron "The Rainband Spectroscope." It ought to 

 have a fixed slit, and in addition a milled wheel at the side for 

 the easier adjustment of the focus. The author concludes by 

 giving a set of hints to ob-.ervers for taking weather observations 

 with a pocket spectroscope. — Rai ifall on and around Table 

 Mountain, Cape Town, Cape Colony, by Mr. J. G. Gamble. 

 The author calls attention to the great and in some respects 

 peculiar differences that exist between the quantity of rain that 

 is registered on and around Table Mountain. Tne most striking 

 feature is the small fall on the signal hill. The signal hill, other- 

 wise called " the Lion's Rump," lies to the west of Cape Town, 

 between it and the Atlantic. The average annual fall there is 

 only 15 inche-;, while the fall at the western foot is 21 inches, 

 and in Cape Town 27 inches. The signal hill is 1143 feet above 

 the .sea. The fall at Platteklip, on the northern slope of 

 Table Mountain, overlooking Cape Town and 550 feet above the 

 sea, is considerable, namely 45 inches. The greatest fall is at 

 Waai Kopje, about half a mile to the southward of the highest 

 point of the mountain, at an elevation of 3100 feet, or 450 feet 

 below the top. Another station on Table Mountain further 

 south — that is, to the leeward in the rainy season — and 2500 feet 

 above sea-ljvel, has only 39 inches. The eastern suburbs, 

 Rondebosch, Newlands, and Wynberg, all have a comparatively 

 abundant rainfall, 40 to 50 inches and upwards, the greater part 

 of which falls in winter time. — On the cause of the diurnal 

 oscillation of the barometer, by Dr. R. Lawson. The 

 object of this paper is to show that the durnal oscillation of the 

 barometer is mainly due to the combination of the earth's 

 rotation with its orbital motion. 



Paris, 



Academy of Sciences, November 28. — M. Janssen in the 

 chair. — On the most general equations of double refraction 

 compatible with Fresnel's wave surface, by M. Maurice Levy. 

 Whatever view be taken of polarized light in a plane, whether 

 it be regarded as the effect of an elastic or electro-magnetic 

 disturbance, whether it result from rectilinear vibrations or from 

 mean rotations (vortices), or from any other cause, it is certain, 

 as remarked by Maxwell, that this cause is measurable by a 

 quantity which is in the nature of a vector. This vector, 

 whether it ba a vibration or a force, the axis of a vortex or of a 

 magnetic momentum, or aught else, is here called a luminous 

 vector, and an attempt is made to determine its most general 

 expression compatible with Fresnel's wave surface. — On the 

 movement of cirri and their relations to cyclones, by M. H. 

 Faye. These phenomana are compared to the action of a river 

 on which floating ice is borne along. Whenever an eddy is 

 formed, the nearest fragments of ice are seen to be drawn within 

 its influence, following its spiral movements and disappearing 

 with it on reaching the centre, while the masses lying beyond 

 its influence continue to drift with the stream. Precisely 

 analogous phenomena are presented by the cirri carried along 

 by atmospheric currents in the higher regions. They arc in the 

 same way sucked down by the gyratory action of the whirlwind, 

 giving rise in the lower regions to heavy rains, hail, and thunder- 

 stornrs, while the more distant clouds continue to follow the 

 general course of the wind. — Researches on the importance of 

 consumi)tive patients breathing a pure ajr uncontaminated by 

 pulmonary exhalations, by MM. Brown-Sequard and d'Arsonval, 

 These remarks are made in connection with an apparatus sub- 

 mitted to the Academy, which has been constructed for the 

 purpose of removing from bedrooms all the air exhaled by one 

 or more persons. The importance is shown of thus purifying 

 sick-rooms, hospital wards, &c., especially when occupied by 

 patients suRering from affections of the lungs. — On a class of 

 differential equations, by M, R. Liouville, Here are studied 

 more especially the differential equations, amongst which are 

 comprised all those of the geodetic lines.— Action of vanadic 

 acid on the fluoride of potassium, by M. A. Ditte. It is shown 

 that vanadic acid in combination with the fluoride of potassium 

 yields compound substances more or less rich in fluoride. But 

 in the presence of oxygen a certain quantity of potassa is de- 



