548 



NATURE 



[[April lo, 1879 



necessary to determine the coefficients of expansion of the 

 particular bars on which the graduations were made. In the 

 present case the coefficient was found to be '0000097 by a 

 process extremely simple and effijctive. The relations between 

 water and air contact also seem to be well determined by this 

 method of investigation. — Dr. J. J. Putnam showed a. penduh/m 

 myograph, modified mainly for the sake of economy, from that 

 of Wundt. The pendulum itself is made of the thickest plate- 

 glass, and arranged so as to l)e moved up and down, with the aid 

 of a racket and a counterpoise, together with the stage bearin;^ 

 the movable connections described by Wundt. Since for each 

 position of the pendulum a tracing of given length would have a 

 diffisrent significance from that in any other position, enameled 

 cards were prepared with lines upon them diverging from the 

 point of suspension, the intervals between which corresponded 

 to •01" when the amplitude of swing was 20°. By means of 

 this apparatus the reliability of Mareyi's tambour had been tested, 

 with a view to its u e in time-experiments in physiology. The 

 delay for the tambour used, with a tube about 2 m. long, was 

 found to be nearly 'oi", varying not more than '002" to '003" 

 under impulses of different character and strength. 



Geneva 



Society of Physics and Natural History, December 

 19, 1878. — M, God. Lunel spoke of the variations of colour 

 presented by the squirrel, and cited some cases of albinism 

 of that animal in a special locality of the Valais. — Prof. iJrun 

 described observations of the phenomenon known as "rain 

 of blood," made by him on May 14 last, on the Jebel Sekra, a 

 summit of the Rist, at the western extremity of the Atlas, in 

 Morocco. He observed it in the form of spots of a very bright 

 red appearing in the rocks, and one to a mixture of siliceous 

 sand and very fine lime, with abundance of unicellular algae of 

 the species Protoco ais fluvalis, and containing especially 

 peroxide of iron. — M Wm. Barbey informed the Society of the 

 gift recently made by Sir J. Hooker to the Museum of Lausanne 

 of the herbarium of the botanist Gaudin of Nyon. 



January 2, 1879. — Prof. Graebe made a communication on the 

 discovery of alizarine in the various colouring matters extracted 

 from it, and particularly on alizarine allies. — M, Alph. de 

 CandoUe gave an account of the number of specimens contained 

 in his herbarium, commenced by his father in 1798. At the 

 time of the death of the latter in 1841, the herbarium contained 

 161,748 specimens; now it contains 287,636 belonging to 

 8o,oco or 90,000 vegetable species. 



Paris 



Academy of Sciences, March 31. — M. Danbreein the chair. 

 — The following papers were read : — Conformity of the systems 

 of fractures obtained experimentally with the systems of joints 

 which traverse the cliffs of Normandy, by M. Daubree. These 

 joints form two systems, and the general effect is like that pro- 

 duced in a plate by weak torsion.— Convenience of special de- 

 nominations for different orders of fractures of the earth's crust, 

 by M. Daubree. He proposes the name diaclase for a fissure 

 produced by rupture ; paraclase, to express that the fracture is 

 accompanied by displacement ; and lithodase, as a general term 

 includmg the two large groups now specified. — New process for 

 the gau^ng of rivers, by M. Boileau. This process is based on 

 the property of water-courses, that at the surface there are two 

 streams whose velocity of translation is equal to the mean velocity 

 of the current. The hydrometric operations are reduced to use 

 of afloat.— On the last floods of the Seine, by MM. Lalanne 

 and Lemoine, Last winter was marked by two successive floods 

 reaching (at a short interval) very nearly the same high level 

 (6-21 m? at the Pont Royal on January 8 and 6*05 m. on February 

 24). Since 1872 M. l.emoinehas organised, under M. Belgi-and's 

 direction, a system of warnings of flood (three days previous) 

 '^or the Seine and its larger affluents. They are sent by tele- 

 graph or otherwise to seventy four persons in Paris and sixty- 

 seven outside of Paris, and have proved very correct. — On some 

 observations of glazed frost similar to that of January last, and 

 on the mode of formation of hail, by M. CoUadon. In large 

 hail-storm^, the cumuli producing them are divided into several 

 distinct groups, insulated electrically from each other by sections 

 of dry and cold air, resembling smoke-columns from several 

 chimneys. The columns of hail the author conceives as a huge 

 descending piston ; hence the violent whirling movements of 

 wind near the ground, and the descent of cold, dry, highly 



electrified air from the upper regions, to restore equilibrium ; 

 this air divides the clouds into nearly vertical columns ; hence 

 the peculiar forms of lightning during those storms. — M, Du 

 Moncel presented a work entitled " L'Eclairage Electrique." — 

 Prof. Lawrence Smith was elected Correspondent in Mineralogy 

 in room of the late Sir Charles Lyell. — Chemical researches on 

 a filamentous matter found in the excavations of Pompeii, by 

 M. de Luca. The substance (which seemed formed of numerous 

 filaments) was black and almost completely carbonised ; on simple 

 pressure with the fingers it was reduced to powder. The threads 

 seem to have been flax or hemp, altered by various natural 

 agents underground during eighteen centuries. — On the cost of 

 constructing lightning-conductors, by M. Melsens. His system 

 applied to the large new barracks at Etterbeck-laz-Bruxelles, on 

 buildmgs occupying 20,000 square metres, will be less than 

 6,coo francs. — Observations of Planet 193, discovered at Mar- 

 seilles Observatory, by M. Coggia, February 28, 1879, com- 

 municated by M. Stephan. — On two equations with partial de- 

 rivatives relative to the multiplication of the argument in elliptic 

 functions, by M. Halphen. — On cylindric or logarithmic 

 potential with three variables and its employment in the theory 

 of equilibrium of elasticity, by M. Boussinesq. — Anomaly pre- 

 sented by magnetic observations of Paris, by M. Flammarion. 

 Since 1870-71 the last maximum of sun-spots and of diurnal 

 variation of the decimation-needle, the amplitude of this varia- 

 tion has decreased everywhere except at Paris ; here it seems 

 stationary; and even the year 1877, which should approach a 

 minimum, presents a maximum. Some like anomalies are ob- 

 servable in previous times. — On the thermal and galvano- 

 metric laws of the electric spark produced in gas, by M. 

 Villari. En resume, the thermal and galvanometric deflec- 

 tions produced, the former by the spark, the latter by the 

 discharge of a condenser, are proportional to the quantity of 

 electricity which produces them, and to the length of their active 

 circuits. — Magnetic rotatory power of gases at ordinary tempera- 

 ture and pressmre, by M. Becquerel. With improved apparatus 

 he has not only got the rotation-effect but been able to measure 

 it with precision. He gives results for coal-gas, &c. — On 

 the magnetic rotatory power of vapours, by M. Bichat. The 

 experiments were like the Strasburg ones, but with a brass 

 instead of an iion tube (which is objected to as forming a hollow 

 electromagnet). — Pressure exerted by galvanic deposits, by M, 

 Bouty. A cylindrical thermometer bulb covered v ith gold leaf 

 or silver is made negative electrode in decomposition, e.g., of a 

 salt of copper ; the rise of mercury when deposit occurs is noted. 

 All metals, zinc included, exert pressure thus ; but the pressure 

 is not necessarily normal nor the same at all points, and cannot 

 serve directly as a measure of the phenomenon ; it is the result 

 of a change of volume of the metal in deposition. — On the alka- 

 lies of pomegranate, by M. Tauret. —On the formation of car- 

 bonic acid, alcohol, and acetic acid by yeast alone, without 

 oxygen, and under influence of this gas, by M. Bechamp.— On 

 glazed frost observed in Florida, by Mr. Collin, 



CONTENTS Pagb 



Johannes Mueller's Classification of Passeres 523 



Our Book Shblf: — . ,„ . ,, 



" Proceedings o£ the London Mathematical Society 327 



Lktteks to I HH. Editor : — '^ 



Brorsen's Comet.- Capt. G. L. Tupman • ■ • 527 



Madagascar Forms in Africa.— Prof . W. T. Thiselton Dyer . . 527 



Transportation of Seeds.— Consul E. L. Layard 527 



Rayons de Crepuscule.— Consul E. L. Layard ....... 527 



Salmon in Rivers of the Pacific Slope.— Geo iGU M. Dawson . . 528 



The Marsupials of Australia.— Henry Weld Blundell. ... 528 



Measuring the Velocity of Sound in Air.— M S^Q 



Snow Flakes.- Frank E. Lott 5'" 



Rats and Water-Casks.— E. J. A'Court Smith : 



Heinrich Wilhel.m Dove - 



The Institution OF Naval Architects 5j- 



Ouji A.sTKONo.vin-Ai. Column : — 



Note on 72 Ophiuchi (O. 2). 342) \l 



The Variable Star % Cygni "i 



The Minor Planets in 1879 ,„ 



Brorsen's Comet '^ 



Edison's Lamp „• ' • ' .L ' ' ' ''^J 



EXIKRIJUBNTAL ReSBARCHHS ON THE RePULSIOK RESULTING FRO.M 



Radiation, IL By W. Crookes. F.R.S. (mtA Illustration^ . • 533 

 The Mirror of Japan, and its Magic Quality. By I'roJ. w. i.. 



Avrton {With Illustration) ! 542 



Geogkaphical Notes ..,,.•••• 



Notes . *;^ 



ViRCHOW ON the Plague ^;| 



University and Education.^. Imtelligenck .546 



SdENTiriC SEKIALS ,..•• ''■ , ( 



SOCIBTIBS AND ACADEMUS • 



