3io 



NATURE 



{Jan. 29, 1880 



be moved up or down in guides, and served to produce waves. 

 A movable apparatus indicated on a cylinder the movements of 

 the surface at any point ; the moment of immersion was also 

 indicated. The following results were arrived at: — I. If the 

 body be drawn out and a wave of depression produced, a 

 whole series of other waves follows this, which are of gradually 

 decreasing height. 2. Both the primary and the secondary waves 

 are, from a certain distance from the origin onwards, propagated 

 with uniform velocity, which, for the same depth, is independent 

 of the mode of the immersion. The first primary wave has the 

 greatest velocity ; it coincides with that resulting from Lagrange's 

 calculations. The velocity of the others decreases from wave to 

 wave, so that their length increases proportionally to the distance 

 from the origin. 3. The depth of the first wave is proportional 

 to the volume brought out of the position of equilibrium ; and it 

 decreases inversely as the square root of the distance from the 

 origin (this corresponds to Boussinesq's development). 4. The 

 profile of each secondary wave is a sinusoid, but that of the 

 primary is much more complicated. These results are in con- 

 tradiction to nearly all analytical results on wave motion. The 

 author is prosecuting his inquiry further. 



In an interesting memoir presented to the Belgian Academy, on 

 the influence of theformof masseson their attraction, M. Lagrange 

 arrives at the following theorem, which he considers as funda- 

 mental for the mechanical theory of crystallisari n : A inass of 

 any form, at a distance from its centre of inertia, acts with maxi- 

 mum, mean, and minimum energies in three rectangular directions, 

 and these directions coincide respectively with the three axes of 

 maximum, mean, and minimum inertia of the mass ; the attraction 

 diminishing the more rapidly the less the mass in question. M. 

 Lagrange offers some preliminary considerations on the structure 

 of bodies, and one curious consequence of his formula: is that 

 the molecules of a body are not always distributed symmetrically 

 with regard to the three rectangular directions, owing lo the in- 

 fluence of certain secondary axes of attraction, which is combined 

 with that of the principal axes of inertia. The principal modes 

 of crystallisation of bodies seem to M. van der Mensbrugghe (who 

 reports on the memoir), in perfect harmony with the classification 

 of molecular groups, (1) according to their principal axes of 

 inertia, (2) according to their secondary axes of attraction. M. 

 Lagrange promises, in an early work, a complete solution of the 

 problems of crystalli-ation of 1 olies. 



M. Thollon has recently observed, by the aid of his spectro- 

 scope of high dispersive power, a solar protuberance 1 whose 

 height equalled one-sixteenth of the diameter of the sun, or about 

 55,000 miles. 



Herr Edelmann describes, in Carl's Repertorium, a novel 

 quadrant electrometer in which the needle, instead of being a 

 flat plate, consists of two quadrants cut vertically from a cylinder. 

 This swings concentrically within another cylinder slit into four 

 quadrants, which replace the usual pairs of flat quadrantal 

 plates. The needle and its attached mirror are supported by a 

 bifilar suspension, and the charge is given to the needle by con- 

 necting the cup of concentrated sulphuric acid, into which it 

 dips, with the pole of a Zamboni pile. This latter arrangement 

 is simpler than the usual replenisher and gauge of the well- 

 known Thomson electrometers, but cannot be anything like as 

 reliable. 



Herr BSttger describes a process for steeling copper plates 

 by electrolysis. 100 parts of ferrous-ammonia sulphate, together 

 with 50 parts of sal-ammoniac, are dissolved in 500 parts of 

 pure water, a few drops of sulphuric acid being added to acidu- 

 late the solution. The copper plate connected to the negative 

 pole of a battery of two or three Bansen elements, an iron plate 

 of equal size being employed as an anode. The solution is 

 maintained at from 6o° to 80°. The deposit of iron is of a 

 hard steel-like quality, and is very rapidly formed. 



An acoustico-electrical kaleidoscope, the invention of M, 

 Michelangiolo Monti, is mentioned in Lcs MondlS. It consists 

 of a microphone used in conjunction with an indue ion-coil and 

 a Geissler tube, and is like Edmunds's phonoscope, which it 

 resembles, intended for the optical study of sounds. A complete 

 description of the instrument is not, how ever, given. 



Prof. Graham Bell communicated a notice of "Some Ex- 

 periments relating to Binaural Audition " to the recent meeting 

 of the American Association for the Adva cement of Science. 

 The paper, which contains some extremely valuable observations, 

 will be published in externa in the American Journal 0/ Otology. 



GEOGRAPHICAL NOTES 



In opening the proceedings of the Geographical Society on 

 Monday evening, Lord Houghton read a letter from Sir Bartle 

 Frere, in which he spoke in the highest terms of Dr. Emil Holub 

 as the most competent traveller he had met for a long time, and 

 in which he also expressed the opinion that, with the exception 

 of a very small portion, the Valley of the Zambesi was well 

 suited for Europeans in regard to climatic conditions. After an 

 amusing sketch of his early experiences in South Africa, and a 

 brief account of his two preparatory journeys, Dr. Holub 

 delivered an address, describing vividly and in considerable 

 detail his main journey, which occupied twenty-one months, 

 from the Diamond Fields to the upper waters of the Zambesi. 

 Among other matters, he thus explained how the River Zooga 

 flows at one time to the east and at another to the west. When 

 the Shallow Lake Ngami is filled up by the streams falling into 

 it from the west, its waters pass through the Zooga to the salt 

 lakes on the east, but when these streams do not pour in such an 

 amount of water, the level of the lake becomes very low,| and 

 the Zooga, often largely increased in volume from the over- 

 flowing salt lakes, sends its waters into Lake Ngami. This 

 solution of a curious phenomenon agrees, we believe, with the 

 conclusion arrived at by Major Serpa Pinio. Dr. Holub dwelt 

 for some time on the Marutse Empire, which he considered 

 to be some 400 miles long and 450 broad, and the languages and 

 customs of which he had ample opportunities for studying 

 from his prolonged stay at Shesheke. When examining the 

 country to the north of this place, Dr. Holub was unfortunately 

 prostrated by severe illness, which compelled him to give up all 

 further explorations in this interesting region. He made his 

 return journey through the western Malcalaka region of the Mata- 

 bele country, about which he gave many particulars. Dr. Holub 

 exhibited a very carefully drawn chart which he had made of 

 part of the course of the Zambesi, and gave some information 

 respecting his various collections. These include ethnographical 

 objects, a large number of skins of birds and animals, fishes, 

 insects, reptiles, &c, besides numerous botanic 1] specimens. Dr. 

 Holub hopes that before long he may have an opportunity of 

 exhibiting his collections in London. 



We have received the first number of the new Zcitschrift fiir 

 wissensehaftlicht Geographic, edited- by Herr J. I. Kettler, of 

 Lahr, in Baden, assisted by an imposing staff of German geo- 

 graphers. We expected great things from this new journal, 

 judging from the prospectus to which we referred some weeks 

 ago ; but we confess this first number disappoints us. Fifteen 

 pages are devoted to a discussion of the first landing-point of 

 Columbus, by Dr. R. Pietschmann, surely a great waste of space 

 in a journal that professes to devote itself to scientific geography. 

 The editor takes up seven pages with an article on the position 

 of Brunswick ; the old story of Severstoft's Ferghona expedition 

 is related, and Dr. O. Krummel reproduces his di-cussion of the 

 mean depths of the ocean, which has gone the round of the 

 journals bng ago. Ht\im.' ija/irbuch for 1S79, now out of date 

 almost, is reviewed, r-nd some old letters of Humboldt's are 

 given, interesting only on the writer's account. An elaborate 

 series of small charts are the only maps given, illustrating the 

 paper on Columbus's landing-point. We trust the succeeding 

 numbers will be both more scientific and more novel, else the new 

 journal can scarcely justify its existence. 



Last week the French expedition commissioned to explore the 

 Sahara in connection with the proposed railway left Paris for 

 Marseilles, whence it will sail for Algeria. The expedition will 

 devote its attention mainly to the country south of Wargla, 

 which is too imperfectly known at present to enable a decision 

 to be come to as to the precise route which the railway ought to 

 take. The expedition is under the command of Lieut. -Col. 

 Flatters, who is accompanied by an efficient scientific staff of 

 e^ineers and others. They will be accompanied by an escort 

 of trustworthy frontier Arabs. At the last meeting of the Pans 

 Society of Commercial Geography, M. Masqueray, the Saharan 

 explorer, gave some interesting information concerning the land 

 of Adrar, in the Western Sahara. This he derived from three 

 pilgrims on their way to Mecca, who had been plundered in the 

 desert, and supplied with funds by the French Government in 

 Algiers to continue their pilgrimage. On their return they have 

 promised to conduct the French explorer to their country. Adrar, 

 or Aderer, presents two or three of the chief aspects of the 

 Sahara, which is by no means the universal desert at one time 



