April 1, I 



NA TURE 



527 



oidinates, so that no part of it shall lie without the normal curve. 

 In curves thus obtained, several of which were shown, deficiency 

 in colour-perception is often very clearly marked. By the use 

 or two or more slits in the movable slide, experiments were 

 made upon mixtures of colours, and it was found in all cases 

 that the luminous effect of a mixture of colours was the sum of 

 the luminous effects of its components. It was also found that 

 the colour of the comparison and the quantity of light admitted 

 to form the spectrum were without effect upon the form of the 

 curve. Light from the sun and from an incandescent lamp were 

 similarly examined, though it should be observed that the result 

 for sunlight differs not.ably from that given by Maxwell. An 

 examination has also been made of light after passing through 

 a turbid medium, and an expression of Lord Rayleigh's — 



/' = Ic-^ ~\ 

 where / is the original radiation, /' that after passing through 

 the medium, A. the wave-length of the light, and .v a constant 

 depending upon the medium, has been closely verified. 



Royal Microscopical Society, March 10. — Rev. Dr. 

 Dallinger, President, F.R.S., in the chair. —Mr. J. Beck 

 described his recent visit to the Naples Zoological Station, 

 and exhibited some Tubularia and other organisms with ex- 

 panded tentacles — Dr. Crookshank exhibited an elaborate 

 micro-photographic apparatus by Messrs. Swift. — Mr. Crisp 

 exhibited Helmholtz's vibration-microscope for observing the 

 vibration of tuning-forks, strings, and other bodies, Thoma's 

 microscope for examining the circulation of the blood in the 

 mesentery of dogs and other small mammals, and various other 

 microscopes and apparatus, including Prof. Exncr's new micro- 

 refractometer for detecting differences in the structure of blood- 

 corpuscles, insects' cornea, &c. — An important communication 

 was read from Prof. Abbe, of Jena, announcing the construction 

 of a new kind of glass, by which the secondary spectrum in 

 objectives was eliminated. Two new objectives were exhibited, 

 which were found to present a considerable advance upon those 

 hitherto constructed. — Notes on a new mounting media of high 

 refractive index, and on a process for obtaining diatoms, were 

 read. — Mr. A. D. Michael read a paper on the life-history of 

 an Acarus, one stage whereof is known as LalnJop/wrus talpie, 

 Kramer, and on an unrecorded species of Disparipes. In 1877 

 Kramer described a creature which he found parasitic upon the 

 mole, and treated as a new species, naming it as above ; it re- 

 sembled Koch's Dermaleichns sciurinus ; it was, however, sus- 

 pected that both were immature, hypopial forms. In 1S79 

 Haller discovered the adult form of JX sHufiniis ; he found it 

 upon the squirrel in considerable numbers and in all stages, 

 Koch's supposed species being the hypopial nymph. For some 

 years Mr. Michael has been trying to trace the history of 

 Kramer's Labidophorus, which he frequently found on the mole, 

 but which he could not get to thrive away from its host ; less for- 

 tunate than Haller, he could not find on the mole any Acarus 

 which could be the adult stage. Last December it struck him 

 that he might succeed by getting the moles' nests ; here he 

 found adult males and females of what he thought might be the 

 species ; he also found immature Acari in the ordinary nymphal 

 stage, which he suspected belonged to the same species. By keep- 

 ing these in confinement and carefully watching them he was en- 

 abled actually to see the hypopial nymph, Labidophorus talpiT, 

 emerge from the cast skin of the young ordinary nymph, and 

 the adult males and females emerge from the cast skin of the 

 fully-grown ordinary nymph. Mr. Michael proposes to call the 

 species Glyciphagus crameri. It is a singular species, the males 

 having remarkable comb-like longitudinal ridges under the front 

 legs. Mr. Michael also described the life-history of a new 

 Disparipes, to be called D. exhainiilatus. 



■ Anthropological Institute, March 9. — Mr. John Evans, 

 F.R.S., Vice-President, in the chair. — The election of Mac- 

 cwUough Bey was announced. — Mr. Arthur J. Evans read a 

 paper on the flint-knapper's art in Albania. During a recent 

 journey through Epirus Mr. Evans was so fortunate as to 

 observe, in a street of Joannina, an old Albanian flint-knapper 

 practising his art, and described his method of working. The 

 place where he obtained his flints is about two hours' journey 

 from Joannina. The flints were mostly of t.abular shape, scat- 

 tered in profusion about the summit of a limestone plateau, but 

 Mr. Evans was unable to discover any signs of their having been 

 used for manufacture in ancient times. The strike-a-lights, as 



exposed for sale, are partially cased in ornamental lead sheaths 

 studded with glass gems and otherwise adorned with something 

 not unlike the ancient "honeysuckle" pattern. Compared 

 with old English, French, and German forms, the Albanian 

 flints show the peculiarity of being chipped on both faces instead 

 of presenting one flat side, and they are fashioned with a minute 

 care that recalls the beautifully even surface-chipping of Neo- 

 lithic times. — The following communications were read by the 

 Secretary : — Notes upon a few stone implements found in South 

 Africa, by \V. H. Penning, F.G. S. ; and notes on some pre- 

 historic finds in India, by Bruce Foote, F.G.S. — Dr. Garson 

 exhibited and described Broca's stereograph and some other 

 anthropometric instruments. 



Paris 



Academy of Sciences, March 22. — M. Jurien de la 

 Graviere, President, in the chair. — On the constitution of the 

 eartli's crust, by M. Faye. It is argued that the surface of the globe 

 cools more rapidly and to a greater depth under the oceans than on 

 the continents, because heat radiates more freely through liquid 

 than through solid bodies. And as this discrepancy has existed 

 for millions of years, the crust of the earth must now be denser 

 under the waters than under dry land. Hence, in the pendu- 

 lum observations and other calculations made relative to the 

 figure of the globe, no account should be taken of the attraction 

 of the continental masses lying above sea-level, this excess of 

 matter being compensated lower down by a corresponding 

 diminution of density. In the same way no account should be 

 taken of the feeble attraction of the oceans, because this also is 

 compensated a little lower down by the greater density of the 

 solid crust under the oceanic basins. The same conclusion is 

 pointed at by the now completed triangulation of India, Col. 

 Clarke remarking that i1 would seem that these pendulum ob- 

 servations have established the fact {previously indicated by the 

 astronomical observations of latitude in India) that there exists 

 some unknown cause, or distribution of matter, which counter- 

 acts the attraction of the visible mountain masses. — On the 

 flexion of prisms, by M. H. Resal. A source of error is de- 

 tected and corrected in the memoir on the flexion of prisms 

 published by M. de Saint- Venant in 1856, the last in which he 

 occupied himself with the subject. — Description of an instru- 

 ment intended to produce at pleasure an invariable quantity of 

 electricity, by M. Marcel Deprez. This invention, which has 

 already been successfully tested in several experiments con- 

 ducted by M. Minet at Creil, has for its object the easy repro- 

 duction of the unit of electric quantity known by the name of 

 coidotiih at all times and under all conditions of temperature and 

 pressure. — Account of a spherical absolute electro neter, by M. 

 Lippmann. — Note on the poisons normally present in animal 

 organisms, and particularly on those of the urine, by M. Ch. 

 Bouchard. — On the development of a holomorphous function 

 in a series of polynomes in any area, by M. P. Painleve. — On 

 the calorimetric study of metals at high temperatures, by M. 

 Poinchon. In this paper the author continues the researches of 

 Pouillet, Weber, and VioUe, and here deals more especially 

 with the common metals and some alloys of platina. — Oneffluvo- 

 graphy, a method of obtaining images by effluvium, by M. 

 D. Tommasi. The author submits the first results of his re- 

 searches on a process for obtaining, by the sole action of electric 

 effluvium, the eftects realised by the employment of light in 

 photography. His experiments tend to show that the effluvium 

 produces the same effects as the ultra-violet rays, and that 

 there must consequently exist a connection between the two 

 extreme ends of the spectiiim. This connection is consti- 

 tuted by what he provisionally calls electric rays. — On the 

 separation and quantitative analysis of copjjer, cadmium, 

 zinc, nickel, cobalt, manganese, and iron, by M. Ad. 

 Carnot. Having already shown how copper may be sepa- 

 rated from cadmium, and cadmium from zinc, by means of 

 the hyposuI]Dhite of ammonia and soda, the author explains 

 his process for separating zinc, nickel, or cobalt, manganese, 

 and iron by means of sulphuretted hydrogen, the state of the 

 liquids being modified by successive precipitation. — On the 

 elements of sugar of milk in plants. In continuation of his 

 previous paper the author shows that the mucous substances of 

 plants, gums, pectine, mucilage, &c., contain galactose identical 

 with that of the sugar of milk ; and further, that these mucous 

 substances exist in vegetable aliments in such quantities that 

 they are able to furnish the galactose which enters into the con- 

 stitution of the sugar of milk secreted by the mammary glands 



