April 6, 1883.] 



SCIENCE. 



257 



proportion of moUusks, principally lamellibraiichiiitos, 

 is larger. Ecliinoderms are also of more frequent 

 occurrence. 4°. The eocene, the most important for- 

 mation in the island, which serves as a point of de- 

 parture of comparisons between the formations. It 

 lies at the base of the miocene, and rests uncomform- 

 ahly on the very inclined and dislocated beds of an 

 older system, probably cretaceous. It contributes 

 chiefly to the formation of the first range of hills paral- 

 lel to the coast. The ujjper part consists of fossilifer- 

 ous limestones dipping 10'=-12° N.W. ; and below are 

 various beds of clay and limestone. A cephalopod 

 (Aturia zigzag Sow.) occurs, with a large number of 

 gasteropods, lamellibranchiates, some echinoderms 

 and corals, and many Orbitoides Mantelli. 5°. The 

 cretaceous, in which no fossils are found. It underlies 

 the tertiary and overlies the western group of moun- 

 tains, which some geologists have considered Jurassic. 

 The general strike of its beds is east and west, and 

 their dip about 50° S. or SS.E. In this formation 

 occur tTie numerous deposits of asphalt, which appear 

 to be contemporaneous with certain igneous erup- 

 tions, none of which have affected the tertiary. 



The eruptive rocks have been called ' Serpentinica 

 formacion,' because serpentine is the prevailing rock 

 in them. The characters of the rock are vei-y varia- 

 ble. The serpentine is frequently associated with dial- 

 lage, and yellowish-green olivine often abounds in 

 the darkerand more compactrock; there is also much 

 oxide of iron and some oligist iron. The centre and 

 highest part of the eruption is often occupied by 

 diorite, then the olivine and diallage serpentine, and 

 outside a talcose serpentine of brilliant lustre. 



Lists of the fossils found in the miocene and eocene 

 are given with the localities in which they occur. 



M. Fernandez de Castro, in a lecture on the pale- 

 ontological proofs that the island of Cuba was united 

 to the American continent, says lie believes that all 

 the great geological divisions are represented in the 

 island; but he adduces almost no evidence in support 

 of this assertion. Those interested in the subject will 

 find a bibliography of works relating to the geology 

 of Cuba in vol. iii., p. 62. — [Bol. com. mapa r/eoL 

 Espana. vii.) J. b. m. [545 



METEOROLOGY. 

 Spectrum of the aurora. — Professor S. Lem- 

 strom, chief of the Finnish meteorologic observatory 

 at Lodan Kylii (lat. 67° 24' N., long. 26° 36' E.), has 

 tried a novel experiment for determining practically 

 the nature of the aurora. He placed a galvanic bat- 

 tery with conductors, covering an arc of 900 square 

 metres (98 feet square), on the hill Oratunturi. He 

 calls the arrangement a streaming ai^paratus. The 

 conductors were constructed of uncovered copper 

 wires, provided at each half-metre with fine erected 

 points. The wire was led in slings to the top of the 

 hill, and reposed on the usual telegraph-insulators. 

 From one end of this wire a covered copper wire 

 was conducted, on insulators, to the foot of the hill 

 (600 feet high), and there joined a plate of zinc in- 

 terred in the earth. In tills circuit was put a gal- 

 vanometer. Professor Lemstrdm found the hilltop 

 to be generally surrounded by a halo yellow-white in 

 color, which faintly but perfectly yielded the auroral 

 spectrum. This, he states, furnishes a direct proof 

 of the electrical nature of the aurora, and opens a 

 new field in the study of the physical condition of 

 the earth. Further experiments in Enare, near Kul- 

 tala, on the hill Pietarintunturi, confirm the above 

 results. On Dec. 29, 1882, a straight beam of au- 

 rora was seen over the galvanic apparatus. — {Nature, 

 Feb. 1.) H. A. u. [546 



Meteorologic council of England. — There 



will be published soon, by the Engli-sh meteorologic 

 council, 'Contributions to our knowledge of the me- 

 teorology of the arctic regions.' These will consist of 

 observations, taken almost entirely by British ships, 

 from 1819 to 1873. 



The council has also resolved upon obtaining data 

 for synchronous weather-maps for the Atlantic Ocean 

 for the thirteen months, August, 1882, to September, 

 1883, inclusive. [Charts for October, during the West- 

 India hurricane season, would be an important addi- 

 tion.] The council publislies 78 per cent of its 

 forecasts of wind and weather as verified. It has also 

 instituted an investigation of the cause and character 

 of London fogs, the best form of thermometer-screen, 

 Stevenson's or Prof. Wild's metallic screen, the best 

 manner of determining moisture in the air, and the 

 motion of the upper air-currents. All these are still 

 in progress. The latter experiments have been tried 

 by firing six-pound shells with fuses of fouiteeii sec- 

 onds. The vertical height reached before the explo- 

 sion was 2,896m. (9,500 feet). The smoke cloud was 

 clearly visible under a blue sky, and remained so for a 

 considerable time. 



The council has made inspections of all the first 

 and second class stations. A noteworthy fact has 

 been brought out by the inspector of the stations in 

 England: namely, that at some stations the abnormal 

 deviations of the wind-direction from local causes is 

 very great; e.g., at Shields, the vane points 22° to 

 the right of the true direction for all except south- 

 west winds. — {Eep. meteor, council Royal soc, 1882.) 

 H. A. H. [547 



PHYSICAL GEOGSAPHY. 



The Gleisen valley, near Munich. — A recent 

 study, by Chr. Gruber, of this dry valley in the Ba- 

 varian plain, shows its connection with the period of 

 glacial extension from the Alps, down the valley of the 

 Isar, to the line of morainal hills, when the overflow- 

 streams from the melting ice cut out channels now 

 abandoned. — {Ausland, 188:3, 76, 87. ) w. M. D. [548 



Ice-caves. — Professor Fngger read an entertaining 

 paper on ice-caves at the fourth international alpine 

 congress at Salzburg last summer, in which he showed 

 that the common idea of the summer growth and 

 winter melting of the cave-ice is incorrect, although 

 supported by high authority, as the elder Pictet, 

 Murchison, Herschel, and others, and generally ac- 

 cepted in text-books. This error is doubtless based 

 on the coolness of the caves in comparison with sum- 

 mer air, and tlieir ajaparent warmth in the colder 

 months, as well as on insufficient observations. 

 Equally wrong is the view sometimes suggested, that 

 the ice of caves survives from the glacial period. The 

 grotto of La Baume, near Besan^on, was known to 

 contain ice in l,i92; but in 1727 it was completely 

 emptied by the duke of Lfivi, to supply his army, en- 

 camped near by ; yet in 1743 the bottom was covered 

 again with ice, and a dozen ice-columns two metres 

 high were formed. It is found by direct measure 

 that the summer temperature of ice-caves is a little 

 above freezing; but in winter it is several degrees 

 below, the cold being derived from air that sinks in 

 from the surface. Water tricl<les in at the tempera- 

 ture of the enclosing rocks, but is then soon frozen ; 

 and, if enough ice accumulates, it will last over the 

 following summer season of melting. This is a sim- 

 ple and sufficient explanation. Summer evaporation 

 has no effective share in producing cold, as the cavern 

 air is very damp. Fifty-six ice-caves are known in 

 the Alps, eight in the Jura and the Carpathians, four 

 in middle Germany, and many more elsewhere. 



