JULV 25. 1895] 



NA TURE 



•joa. Orders have been issued by the Persian Government for 

 the town to be rebuilt near Hai Hai, a place six or seven miles to 

 the south-east, which experience has shown to be safe from 

 <Iestructive shocks. 



The histof)' of the Russian Biological Station, on the island 

 of Solowet/k in the North Sea, has already been given in our 

 columns (Nature, November 1894, p. 83). One of the most 

 interesting of the results achieved by the naturalists of the 

 laboratory has been the discovery of a remarkable lake on the 

 island of Kildine in the Arctic Ocean. This lake, which is 

 completely separated from the sea by a narrow strip of land, was 

 discovered by the Russian naturalist, M. Merzenstein, who 

 was struck by finding in the lake a fish which is exclusively 

 marine in habit, namely the common cod. Further observations 

 by M.M. I-'aussek and Knipowitsch have elucidated the peculiar 

 features of the fauna of the lake. On the surface the water is 

 fresh, and is inhabited by fresh-water animals, such as Daphnids, 

 &c. ; this water is brought to the lake by streams from a neigh- 

 bouring marsh. Under the superficial layer of fresh water is 

 /ound salt water, supporting a Marine fauna — Sponges, Sea- 

 anemones, Nemertines, Polychietes, marine Molluscs (Chiton, 

 j'Eolis, AstarU), Starfish, and Pantopods. There is even a 

 regular littoral zone beneath the fresh water, characterised by 

 small Fuci. The bottom of this lake is covered with mud ex- 

 haling an odour of sulphuretted hydrogen, and is not inhabited. 

 The water of the lake shows a slight ebb and flow, attaining a 

 vertical height of only a few inches, while the tides in the 

 adjacent sea are considerably greater. This fact would appear 

 to point to the existence of some subterranean communication 

 .between the lake and the sea. 



Some important additions to a knowledge of the latest 

 Mesozoic and early Tertiary mammalia have recently been made 

 irom Patagonia and the Uinta Basin. From the former place a 

 collection of ungulates of very late Cretaceous date is described 

 by Seiior V, .^meghin in the Bol. Inst. Geograjico Argentina, 

 t. XV., II and 12. The most important is a new genus, 

 Pyrothcrium, which is made the type of a new sub-order, 

 regarded a.s ancestral to the Proboscidea, and showing marsupial 

 affinities. A number of other new genera are also described, 

 -and it is anticipated that when the fossil localities, which are 

 •very difficult of access, have been more fully investigated, still 

 more valuable infonnatiim on the late Mesozoic mammalia will 

 .be obtained. Large Dinosaurs and birds also occur in these 

 beds. 



Pkok. II. F. OsEORN reports in the Bull. Amer. Mm. Nat. 

 Hist., New York, vol. vii.,art. 2, on a more extensive collection 

 than has hitherto Vjeen obtained from the Eocene beds of the 

 Uinla Basin. Beneath the true Uinta fauni comes one which 

 is intermediate between it and the Bridger and Washakie faunas, 

 .>nd thus supplies a most important link in the faunal succession 

 of this province, while at the same time it shows affinities to the 

 Miixrene fauna of the White River. Among the mammalia 

 found in this transitional fauna are a monkey, and species of 

 Tclmatotheriuin, which definitely confirm the view that that 

 genus was ancestral to the Titanotheria. It is expected that 

 Still more valuable results may be got from a more thorough 

 .exploration that is being made this year. 



The application of electricity to locomotion has recently 

 made notable progress in the United States. At a trial of 

 electric motors at Nantasket Beach, near Boston, a few- 

 days ago, it is stated that a speed exceeding sixty miles 

 an hour was attained ; and the experiment demonstrated 

 ihe utility of this motor for suburban traffic. The system 

 went into practical and regular operation on the Nantasket 

 Beach Railway at the end of June. A successful test has also 

 NO. 1343, VOL 52] 



been made at Baltimore of the electric ocomotive designed to 

 draw trains through the tunnel, 7430 feet long, in that city. 

 This and its companion — the first locomotives of the kind ever 

 built — have each two trucks and eight wheels, sixty-two inches 

 in diameter. Flexibly supported on each truck are two 

 six-pole gearless motors, one for every axle. A maximum speed 

 of fifty miles an hour is to be developed, and it is guaranteed that 

 the locomotive will pull 1200 tons at a speed of thirty miles an 

 hour. When coupled to a six-wheel New York Central 

 locomotive, the electric locomotive pulled it up and down the 

 track at will, against the pull of the steam locomotive. 



.\t a recent meeting of the Societe Francaise de Physique, M. 

 Pierre Weiss gave an account of the results of his experiments on 

 the aelotropic magnetic properties of crystallised magnetite. 

 The magnetisation curve of magnetite crystallised in the cubic 

 system presents the same general features as those of iron, 

 nickel and cobalt. The magnitude of the magnetisation 

 (i.e. the permeability), however, varies with the inclination of 

 the magnetising field to the crystallographic axes. Experiments 

 have been made by a ballistic method suitably modified so as to 

 permit of observations being made on very small specimens. 

 The results thus obtained have been confirmed by other experi- 

 ments in which a small disc of magnetite was rotated in a strong 

 magnetic field, and the variations in the induction measured by 

 means of a small coil surrounding the disc and connected to a 

 ballistic galvanometer. The discs examined were cut parallel to 

 the faces of the cube, octahedron and rhombic dodecahedron. 

 If the results are expressed by drawing radii vectores from a 

 given point of such length that they represent the magnetisation 

 of the specimen in that direction when saturated, the surface 

 which contains the ends of all these radii vectores is a cube with 

 rounded edge";, and with its faces slightly hollow. The 

 magnetisation is the same in all directions contained in a plane 

 parallel to one of the faces of the octahedron, S3 that the above- 

 mentioned surface is cut by such a plane in a circular section. 

 .\n experiment illustrating this aelotropic property of magnetite 

 was shown before the Society. A small disc of magnetite placed 

 on a plate of glass between the pjles of a strong electro-magnet, 

 turne<l so that one of its axes of maximum permeability was 

 parallel to the field. Besides the difference which these experi- 

 ments show between a body crystallised according to the cubic 

 system and an isotropic body, they also show that the theories 

 which regard magnetisation as resulting from the orientation of 

 particles of fixed magnetic moment are insuflicient to explain 

 the magnetisation of crystalline bodies. 



During his recent visit to the Algerian Sahara, M. Janssen 

 made some decisive observations concerning the absorption bands 

 .near the D line of the solar spectrum, supposed to be due to 

 atmospheric oxygen. The object was to test whether these absorp- 

 tion bands correspond to those observed on transmitting white 

 light through a tube containing condensed oxygen. In some 

 previous experiments on this question, M. Janssen had obtained 

 these bands by means of a tube 60 m. long, containing oxygen 

 compressed up to 6 atmospheres. .A.n account of the Sahara 

 observations is given in the Coinptes rcndiis, together with a 

 theoretical investigation concerning the equivalent height of the 

 atmosphere. Starting with the remarkable law discovered by 

 M. Janssen that the absorptive power of a gas is proportional to 

 the thickness traversed and to the square of Ihe density, the 

 integration of the different layers of the atmosphere with their 

 different densities gives 3981 m. as the equivalent thickness for a 

 vertical ray of light. But since the density of oxygen is only 

 0'2o8 of that of the atmosphere, this number must be multi- 

 plied by 0-043, ^^^ square of that density. This gives i;2 m. 

 as the equivalent thickness of the oxygen layer. This thick- 

 ness, at a pressure of one atmosphere, would not be ufficient 



