2 6 



NA TURE 



[July 19, 1900 



horological technology, is a noteworthy characteristic. The 

 courses of work in this as well as the other subjects show that 

 sound instruction in the principles and practice of the chief 

 branches of engineering can be obtained at the Institute. 



SCIENTIFIC SERIALS. 



American Journal of Science, July. — Energy of kathode rays, 

 by W. G. Cady. This is a translation of a paper already 

 published in the Annalen der Physik. — Volcanic rocks from 

 Temisconata Lake, Quebec, by H. E. Gregory. The volcanic 

 rocks consist of fine tuff and coarse amygdaloidal conglomerate 

 or breccia. They are interbedded with Niagara sediments, and 

 this helps to determine the time when widespread volcanic 

 activity gave rise to the numerous small areas of tuffs and lavas in 

 the Maine-Quebec region. — Interpretation of mineral analyses, 

 and a criticism of recent articles on tne constitution of tour- 

 maline, by S. L. Penfield. It is safe to assume that the close 

 approximation of atomic ratio to whole numbers constitutes the 

 strongest argument that can be advanced in support of the 

 excellence of an analysis and to correctness of the derived 

 formula. The author criticises the formulae proposed by Clarke 

 and Tschermak, and maintains that it is definitely proved that 

 the empirical formula of the tourmaline acid is 11206281402]. — 

 Carboniferous boulders from India, by B. K. Emerson. The 

 author describes and illustrates some striated carboniferous 

 boulders which remove the doubt as to the former existence of a 

 carboniferous glacial period. — The statement of rock analyses, 

 by 11. S. Washington. The author proposes a regular system 

 of stating the results of the chemical analysis of rocks. The 

 oxides are to be enumerated in the following succession : Si02, 

 AljOa, FejO, FeO, MgO, CaO, NaaO, Kp, H.p, COj, and 

 then the rarer oxides, also in definite succession. This will 

 enable the geologist to classify the rocks in a purely chemical 

 system and to pick them out at a glance. They can be advan- 

 tageously entered upon a card catalogue. — A string alternator, 

 by K. Honda and S. Shimizu. The authors describe a modifi- 

 cation of Pupin's string interrupter by means of which a 

 continuous battery current can be converted into an alternating 

 current the frequency of which can be readily varied from 30 to 

 1000 per second. — Action of light on magnetism, by J. H. Hart. 

 The author failed to obtain the demagnetisation of iron by light 

 SCtiiig magnetically like an alternating current, until he adopted 

 the expedient of depositing very fine iron films on glass. He 

 then noticed a small but distinct difference in the magnetic state 

 of the iron according to the plane of polarisation of the incident 

 light. 



Bollettino delta Societa Sismologica Italiana, vol. vi. 1900- 

 1901, N. I. — Rules and list of fellows (forty-three national and 

 thirteen foreign). — Vesuvian notices (year 1899), by G. Mercalli. 

 A monthly review of the condition of Vesuvius, with sections on 

 the form and state of the crater, the end of the eruptive phase 

 of 1895-1899, the lavic cupola of 1895-1899, the supposed en- 

 dogenous elevation of the lavic cupola, and the fumaroles of the 

 lavic cupola and fracture. — On the nature of seismic vibrations, 

 by M. P. Rudski (in French). The author contends that super- 

 ficial, and probably deep-seated, rocks are not isotropic media, 

 and that earthquake waves consist of vibrations which are not 

 entirely longitudinal or entirely transversal. — Notices of earth- 

 quakes recorded in Italy (January i to March 14, 1896), by A. 

 Cancani, the most important being the Mexican earthquakes of 

 January 14 and 25, the Greek earthquake of January 22, and 

 distant earthquakes on January 6, 22, and March 7. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, May 17.— " The Circulation of the Surface 

 Waters of the North Atlantic Ocean." By H. N. Dickson, B.Sc. 

 Communicated by Sir John Murray, K.C.B., F.R.S. 



_ In this paper an attempt is made to investigate the normal 

 circulation of the surface waters of the Atlantic Ocean north of 

 40° N. lat., and its changes, by means of a series of synoptic 

 charts showing the distribution of temperature and salinity over 

 the area for each month of the two years 1896 and 1897. 



NO. 1603, VOL. 62] 



The principal conclusions arrived at with reference to the 

 circulation may be summed up as follows : — 



( 1 ) The surface waters along the whole of the eastern seaboard 

 of North America north of (about) lat. 30° N. , consisting partly 

 of water brought from the equatorial currents by the Gulf 

 Stream, and partly of water brought down by the Labrador 

 current, are drifted eastward across the Atlantic towards south- 

 western Europe, and banked up against the land outside the 

 continental shelf. This continues all the year round, but it is 

 strongest in summer, when the Atlantic anti-cyclone attains its 

 greatest size and intensity ; and the proportion of Gulf Stream 

 water is greatest at that season. 



(2) The drifts in the northern part of the Atlantic area are 

 under the control of the cyclones crossing it. The circulation 

 set up accordingly reaches its maximum intensity in winter, and 

 almost dies out in summer. In winter the drifts tend to the 

 south eastward from the mouth of Davis Strait, eastward in mid- 

 Atlantic, and north-eastward in the eastern region. In spring 

 and autumn the movement is more easterly over the whole 

 distance, and a larger quantity of water from the Labrador 

 stream is therefore carried eastward. 



(3) The water banked up in the manner described in (i) 

 escapes partly downwards, partly southwards, and partly north- 

 wards. It occupies the whole of the eastern basin of the North 

 Atlantic, and to the north it extends westward to Davis Strait, 

 being confined below 300 fathoms depth by the ridges connecting 

 Europe, the Faeroes, Iceland, and Greenland. Above that 

 level it escapes northward by a strong current through the 

 Faeroe-Shetland Channel and between Faeroe and Iceland, 

 and by the two branches of the Irminger stream, one west of 

 Iceland the other west of Greenland. 



(As it seems desirable that this northerly current should have 

 a distinctive name, it might be well to call it the European 

 stream, and its branches the Norwegian, Irminger, and Green- 

 land streams respectively. ) 



The strength and volume of the European stream is liable to 

 considerable variation, according to the form and position of the 

 Atlantic anti-cyclone, which causes the amount of banked up 

 water, and the proportions escaping northward and southward, 

 to vary. It is also modified by the strength and direction of 

 the surface drifts in its course. It is, however, always strongest 

 in summer. 



(4) The Norwegian stream is by far the largest branch of the 

 European, and it traverses the Norwegian Sea and enters the 

 Arctic Ocean. The warm water thus sent northward melts 

 enormous quantities of ice, and the fresh water derived from the 

 ice moves southward in autumn, chiefly in a wide surface current, 

 between Iceland and Jan Mayen, which may entirely cover other 

 parts of the Norwegian stream. Part of the surface water also 

 comes southward through the Denmark Strait, but the amount is 

 much smaller, probably chiefly because the melting of the ice is 

 slower, and the channel is longer blocked. 



The Greenland branch of the European current also causes 

 melting of ice in Davis Strait, but the warm winds from the 

 American continent and the water received from the land are 

 probably more effective in increasing the volume of the Labrador 

 current. 



(5) The water from the melted ice is spread over the surface 

 of the North Atlantic during late autumn and winter by the 

 increasing drift circulation, and it is gradually absorbed by 

 mixing with the underlying water. 



(6) The circulation described is liable to extensive irregular 

 variations, corresponding to variations in the atmospheric 

 circulation. 



May 31. — "Influence of the Temperature of Liquid Hy- 

 drogen on Bacteria." By Allan Macfadyen, M.D., and Sydney 

 Rowland, M.A. Communicated by Lord Lister, P. R.S. 



In a previous communication we have shown that the temper- 

 ature of liquid air has no appreciable effect upon the vitality of 

 micro-organisms, even when they were exposed to this temper- 

 ature for one week (about -190° C). (J^oy. Soc. Proc, 

 February i ; ibid.^ April 5.) 



We have now been able to execute preliminary experiments 

 projected in our last paper as to the effect of a temperature as 

 low as that of liquid hydrogen on bacterial life. As the 

 approximate temperature of the air may be taken as 300" 

 absolute, and liquid air as 80° absolute, hydrogen as 21" 

 absolute, the ratio of these temperatures roughly is respectively 

 as 15 : 4: I. In other words, then, the temperature of liquid 



