290 



NATURE 



[Jan. 22, 1880 



the perpendicularity of the light vibrations to the plane of 

 polarisation, by E. Lommel. — On a small alteration of the 

 Bunsen grease-spot photometer, by A. Toepler. — On the refrac- 

 tion of sound-waves, byK. W. Schellbach and E. E. Boehm.— 

 On the specific heat of water according to Dr. Baumgartner's ex- 

 periments, by L. Pfaundler. — Reply to the observation of O. E. 

 Meyer, by L. Boltzmann. — On the application of the telephone 

 to measurements of resistance, by F. Niemoller. — On the motion 

 of claciers, by K. R. Koch and F. Klocke. — On hailstone> with 

 ice-crystals, by Ed. Hagenbach. — On hailstones of uncommon 

 size, by P. Merion. (In a paper prefixed to this number, Prof. 

 Clausius defends himself against s >me aspersions, by Herr 

 Diihring, regarding'his relations to Robert Mayer, apropos of the 

 mechanical theory of heat.) 



The Sitzungsberiehte der natunoisscnschaftlichen Gesellschaft 

 /sis in Dresden (1879, January to June) contain the following 

 papers of interest : — On the recent geographical and geological 

 investigations of the United States of America, by Dr. Geinitz. 

 — On the coal flora of the Lugan coal-pits, by H. Krone. — On 

 the constitution of dichlornitrophenol, by Dr. Schmidt. — On a 

 new form of the influence machine, by Dr. Topler. — On the 

 action of chloride of lime upon absolute alcohol, by Dr. Gold- 

 berg. — On a gas-stove with arrangement for oxidation, by Dr. 

 Hempel. — On a new dye, by Dr. Schmitt. — On the isomerism 

 of ethanes, by Dr. Goldberg. — On the tension of threads and 

 Poggendorff's fall machine, by Dr. Amthor. — On a discovery 

 from the later stone period made in Bohemia, by \V. Osborne 

 (with 5 plates). — On the prehistoric centres of culture in Schles- 

 wig, by Herr Michelsen. — On some objects found by Dr. Schlte- 

 mann in his excavations in Greece and Asia Minor, by Dr. 

 Fiedler. — On a discovery of urns at the Hradischt, near Stra- 

 donic (Bohemia), by W. Osborne. — On the occurrence of Cas- 

 tanea vesca, L., by Dr. Friedrich. — Various smaller botanical 

 papers of minor interest. — On the theory of Watts's centrifugal 

 regulator, by Dr. Ritterhaus. — On some galvanometric methods 

 of multiplication, by Dr. Topler. — Remarks on Wallengrcn's 

 work concerning Linnceus's species of the genus Phryganea, by 

 M. Rostock. — On the Neuroptera of Saxony, by the same ; a 

 most elaborate treatise with complete list and catalogue. — On 

 the Hemiptera fauna of Transcaucasia, by Dr. von Horvath. — 

 Obituary notices of Dr. Eduard Lbsche and H. G. Lud.vig 

 Reichenbach. 



Keale IstUuto Lombardo di Scienze e Lcttere, vol. xii. fasc. 

 xvii.-xviii. — This number contains a survey of the year's work, 

 announcements of prizes awarded (wi.h abstracts of memoirs), 

 and of prize subjects, &c. 



Fasc. xix. — Stratigraphic observations on the precarboniferous 

 formation of Valtellina and Calabrh, by S. Taramelli. — On the 

 dilatation of the heart in disorders of the ventricle, by Prof, de 

 Giovanni. 



Journal de Physique, December, 1879. — We note here the 

 following : — Measurement of the wave-length of obscure calorific 

 rays, by M. Mouton. — Displacement between oxygen and the 

 halogen elements united with metals, by M. Berthelot. — A 

 spectroscope for studying the phenomena of fluorescence, by M. 

 Lauiansky. 



Journal of the Franklin Institute, December, 1879 — On a 

 new theory of the retaining wall, by Prof. Du Bois. — A system 

 of electrical storage, by Professors Houston and Thomson. — 

 Steam boiler explosions, by Messrs. Corbin and Goodrich. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, January 15. — "On Chemical Repulsion," by 

 Edmund J. Mills, D'.Sc, F.R.S. 



While engaged in some researches on the propagation of 

 chemical change, I have incidentally encountered a new order of 

 phenomena, which the title "chemical repulsion" may serve 

 provisionally to designate. A brief outline of the experiments is 

 given in the following paragraphs. 



Upon a glass plate, laid in a horizontal position, is poured 

 enough solution of baric chloride to cover it completely to a 

 considerable depth. On this solution is placed another glass 

 plate, provided with a small central perforation ; when the two 

 plates are firmly pressed together with the hands, most of the 

 solution is extruded, and only a very thin layer of it left between 

 the plates. All excess of the solution having been removed 

 from the outer surfaces of the plates as well as from the perfora- 



tion, some dilute hydric sulphate is now introduced into the 

 perforation. This reagent attacks the baric chloride, throwing 

 down a white precipitate of sulphate ; and, proceeding partly by 

 diffusion, partly by flow, does not cease to widen in every direc- 

 tion its figure of advance, until the edges of the plates are 

 attained. If the perforation is circular, the figure of advance is 

 circular ; in other words, the chemical development of a circle is 

 a circle. 



Let us now suppose the two plates to be square and equal, and 

 let the upper one have two circular perforations, equidistant 

 from the centre of the square, and situated upon its diagonal. 

 Let also two circular developments of baric sulphate be caused 

 to proceed, as before, from the two perforations simultaneously. 

 At first nothing remarkable is observed, but in a short time, the 

 two growing circles begin to exercise a visible retardation on 

 each other's progress ; so that the figure of advance is no longer 

 circular, but oval. [This retardation is of course observed only 

 between the perforations ; and not outside them, where the 

 motion is entirely free.] As the development of the figures 

 continues, so also does the retardation at their neighbouring 

 edges increase ; the final result being (however long the experi- 

 ment may be prolonged), that the other diagonal of the square 

 is completely and permanently traced out in a line of no chemical 

 action. 



The above experiments are of fundamental importance, and 

 they obviously admit of endless variety. Of this, a few illustra- 

 tions may suffice. 



If the upper plate have three perforations, situated on the 

 points of a central equilateral triangle, there are three repulsion 

 iines ; the<e end at the centre of the triangle, where they form 

 a trilocular point, and traverse its sides midway at right angles. 



When the upper plate has four perforations, situated on the 

 points of a central square, there are four repulsion lines ; these 

 end at the centre of the square, where they form a quadrilocular 

 point, and traverse its sides midway at right angles. 



A very beautiful modification of the preceding experiment 

 consists in simultaneously developing a circle from a (fifth) 

 central perforation. This last circle has no means of escape 

 from the surrounding four. The result is, that it eventually 

 forms a square figure bounded by repulsion lines, and having 

 four symmetrically situated repulsion lines at its corners. 



It is easy to demonstrate that the chemical repulsion in these 

 experiments does not depend upon Row. Two superimposed 

 triangular plates, for instance, in neither of which is any perfora- 

 tion, give three repulsion lines on immersion in dilute hydric 

 sulphate. From each corner a line proceeds midway (if the 

 triangle be equilateral) to the centre. In this effect diffusion is 

 alone concerned. 



In addition to hydric sulphate and baric chloride, other pairs 

 of reagents may be used with success ; and I anticipate no diffi- 

 culty in obtaining results in which precipitation is not concerned. 

 A beginning has also been made with experiments in tridimen- 

 sional development. 



The complete explanation of what I have termed "chemical 

 repulsion" will probably demand a varied and considerable 

 amount of experimental work. From some incidents of the 

 investigation, so far as it has hitherto proceeded, I am disposed 

 to believe that the motion in any plane chemical figure is not 

 along the radius, but at right angles to the radius ; and this sup- 

 position will, if verified, explain the repulsion. The existing 

 results afford proof of the following propositions, viz. : — 

 (1) Chemical action can t.ike place at a distance ; and (2) Two or 

 more chemical actions, identical except in position, completely 

 exclude one another. 



Chemical Society, January 15. — Mr. Warren De La Rue, 

 president, in the chair. — The following papers were read : — On 

 the effects of the growth of plants on the amount of matter 

 removed from the soil by rain, by Dr. J. H. Prevost. Soil 

 3 inches deep was placed in two glazed earthenware pans 

 17 inches in diameter on July 21 ; 4 grm. of white clover seed 

 was sown in one, the other being blank. The pans were 

 exposed till October 4. The drainage-water was collected and 

 analysed ; that from the clover soil contained 48"i grains of solid 

 matter per gallon, the other 220. The author concludes that 

 rain removes much more matter from an uncropped than from a 

 cropped soil. — Mr. Wynter Blyth described a simple apparatus 

 for the treatment of substances in open di -lies to volatile solvents. 

 The dish is placed in>ide a cast-iron pan, and covered with a 

 glass bell-jar, with condenser attached, the joint between the 

 bottom of the pan and the bell-jar being made tight with 



