>«. 17, 1878] 



NATURE 



233 



close to the high road leading from Neuwied to Coblenz. It is 

 stated that the noise caused by the fall was very characteristic. 



Three earthquakes were observed at Kirlibaba, in the Buko- 

 wina, on December 2S and 30 respectively. A fourth pheno- 

 menon of this nature was felt at Innsbruck, in the Tyrol, on the 

 3rd inst., at 8 46 p.m. 



Bf.rlin is listening to an interesting series of lectures delivered 

 under the auspices of the Society for African Exploration. On 

 the programme we notice Dr. Nachtigal, " Ancient Dar four ;" 

 Dr. Giissfeldt, "The Arabian Desert ; " Dr. Hildebrandt, 

 "Pictures from Equatorial Africa," Prof, Hartmann ; "Fauna 

 of the Swedish Islands," &c. 



The two African Societies at Berlin, which have hitherto 

 existed independently of one another, have now finally resolved 

 to unite into a single society. 



We have received the first number of The Midland Naturalist, 

 the journal of the associated societies and clubs of the Midland 

 counties, the union of which we referred to some time since. 

 It is a neat and well-printed journal, containing seven good 

 papers, besides miscellaneous matter. Besides the opening 

 address, explaining the foroiation and objects of the Union, there 

 are papers on abnormal ferns, by Mr. E. J. Lowe, F.R. S. ; on 

 an improved aneroid, by Mr. W. J. Harrison, F.G.S. ; on the 

 marine zoology of Arran, by Mr. W. J. Hughes (giving the results 

 of an excursion by the Birmingham Natural History Society last 

 summer) ; Lepidoptera in the Midland Counties, by the Rev. C. 

 F. Tliornewill; Entomostraca, by Mr. Edwin Smith; and a 

 paper on some new features in the geology of East Nottingham, 

 by Mr. J. Shipman. This is a very good start, and we hope 

 The Midland Naturalist will fill a useful place in our scientific 

 literature. Hard.vicke and Bogus are the London publishers. 



Reports from the Bernese Alps state that the amount of 

 snow fal'en during the present month is much greater than has 

 been experienced for a number of years. 



The wolves in Eastern France have become unusually bold 

 durirg this win'.er, and reports are constantly received of their 

 depredations in various parts of the country. In one instance a 

 letter-carrier was driven back by them from his regular route. 



An interesting experiment was lately carried out in the neigh- 

 bourhood of Emmendingen, on the River Danube, to show its 

 subterranean connection with the valley of the Rhine. The 

 river is separated here by a range of Jura limestone from the 

 district drained by the Rhine, and it has long been suspected 

 that the Aach, which has its source in this range and flows into 

 Lake Constance, was really supplied by the Danube. In order 

 to solve the problem, recourse was had to fluorescin, the phtha. 

 lein of resorein, a compound which yields with alkalies magnifi- 

 cent green fluorescent solutions capable of imparting this pro- 

 jitrty to enormous masses of water. A solution of this substance 

 was introduced into the Rhine at Emmendingen, and two and a 

 half days later the bright green fluorescence was visible in the 

 Aach, the source of which is about five miles distant, and lasted 

 for thirty -six hours. This experiment shows most decisively 

 that the Upper Danube shares its water between the Black Sea 

 and the North Sea, and affords a most interesting explanation of 

 the close similarity in the finny inhabitants of the two great 

 European rivers. 



We not'ce the appearance, in Paris, of a French translation of 

 the "Organic Chemistry" of Prof. Fittig, of Strassburg. This 

 work, which in its present form is the tenth edition of the text- 

 book originally issued by Prof. Wohler, has long been a favour.te 

 with the German chemist on account of the scrupulous care and 

 fidelity which have been exercised in preparing each successive 



edition. An English translation was prepared a short time since 

 by Prof. Remsen, of Johns Hopkins University, formerly one of 

 Fittig's assistants, the circulation of which is confined, however, 

 chiefly to America. 



Arrangements are being made for the holding of aa Inter- 

 national Exhibition at Sydney in 1879, under the auspices of the 

 Agricultural Society of New South Wales, It is anticipated that 

 many of the articles shown at the coming Paris Exhibition will 

 be trans-shipped to Sydney. 



A propos of the remarkable relation established by Dr. Kerr, 

 a short time ago, between light and electricity, an interesting 

 experiment has been made by Mr. J. Mackenzie, in Berlin, at 

 the instance of Prof. Helmholtz {Pogg. Ann., No. il). A glass 

 plate, 161 mm. long, 12 mm. thick, and whh tin foil on its 

 opposite sides, from which proceeded copper wires to a Ruhra- 

 korff coil (with six Bunsen elements), or a Holtz machine, and 

 to earth, was supported and covered with larger glass plates, 

 and placed between two Nicols, as in Dr. Kerr's experiment, 

 the light-source being a lamp. The electric action gave no 

 perceptible increase of brightness, nor was any such obtained 

 when polarised sunlight was used to give greater sensibility, and 

 a leaf of mica thick enough to give the violet colour was inter- 

 posed between the glass plate and the analyser. Experiments 

 with oil of turpentine likewise gave negative results. (The high 

 sensibility of the polariscope is demonstrated by distinct experi- 

 ments.) It is therefore concluded that the phenomenon observed 

 by Dr. Kerr is not produced by electric tension itself, but pos- 

 sibly in a secondary manner, through the heating thus caused. 

 Confirmation of this is found in the fact that in Dr. Kerr's ex- 

 periments it was only after about thirty seconds from closure of 

 the circuit that the action reached its maximum ; it also dis- 

 appeared slowly. 



In a paper in the Bullttiii of the Belgian Academy of 

 Sciences (Nos. 9 and 10), Prof. Van der Mensbrugghe dis- 

 cusses the causes of the seemingly spontaneous movements 

 of bubbles of air in levels and of vaporous bubbles in 

 the microscopical cavities of m.ineral?, these researches being 

 part of those into the tension of .surfaces of liquids. Prof. 

 Mensbrugghe explains these movements, as Mr. Hartley also 

 does, by chang::s of tension in the surfaces of liquids produced 

 by changes of temperature ; when the temperature of the liquid 

 at one end of the bulb becomes, for some reason, higher or lower 

 than at the o*her end, however small the difference, the tension 

 of the surface decreases at the warmer end, and the bubble moves 

 towards it. But, a thin film of water remaining on the glass, the 

 surface of the liquid is enlarged at the warmer end, and diminished . 

 at the oppo>iie end, and this, according to experiments of the 

 author, lowers the tempera'ure and increases the tension at that 

 end ; so that if the temperature now ceases to rise the motion of 

 the bubble is not only stopped, but the bubble also returns back- 

 wards. Thus each displacement of the bubble immediately gives 

 ri>e to such forces as tend to produce a motion in an opposite 

 direction ; and the variations of tension produce the more obvious 

 motions the smaller the masses of liquid in which the bubble is 

 swimming. The same explanation may be applied also to the 

 movements of bubbles in microscopical cavities of minerals filled 

 with liquids. In that case, the bubble being produced by the 

 vapours of the liquid, its movements are yet more rapid, as every 

 change of temperature is followed by further evaporation of the 

 liquid, or by condensation, both which alter the dimensions of 

 the surfaces of the liquid and their tension. The author supposes 

 also that the Brownian motions of powders suspended in liquids 

 may be explained in the same way, ard that those powders 

 which absorb most gas will best display this kind of motion. 



Prof. Emilio Cornalia, an eminent naturalist and Director 



