1884.] Mr. P. Jabloclikoff. On a New Voltaic Battery. lil 



singly infinite number : consequently the locus of the vertex contracts 

 in this case into a surface, the orthoptic sphere. The locus of the 

 vertex of a trihedral angle which envelopes a quadric is in general 

 the space bounded by two surfaces. 



Next consider a complex of lines of the nth order; those of its lines 

 which pass thi-ough a specified point form a cone of the nih order ; 

 this cone can be circumscribed by a cube-angle provided the point 

 lies within a certain solid, space. When the complex is of the second 

 order the solid, locus degenerates into a surface, which is a quartic 

 passing through the imaginary circle at infinity ; and when the 

 complex is composed of the tangent lines of a surface of the second 

 order the locus is made up of the surface and its orthoptic sphere. 



Similar considerations hold for the locus of the point of concourse 

 of a triad of tangent lines at right angles. When the complex is of 

 the second order the locus degenerates into a quadric. 



Mr. Larmor has briefly considered the problem of a surface 

 constrained to touch three surfaces, deducing as a special case that 

 the locus of the vertex of a cube- angle whose faces touch a quadric 

 or three confocal quadrics is a sphere. 



IX. " On a New Form of Voltaic Battery." By PAUL JABLOCH- 

 KOFF. Communicated by WARREN DE LA RUE, M.A., 

 D.C.L., Ph.D., F.R.S. Received May 12, 1884. 



The battery which I have the honour to bring under the notice of 

 the Royal Society is one of high electromotive force, namely, about two 

 and three quarter volts, and a single cell consequently decomposes 

 water; it is very light and portable, and convenient for many purposes. 

 The electro-positive element is sodium, the electro-negative element 

 is either carbon, spongy platinum, copper, or other metallic gauze; no 

 fluid is used in which to immerse the plates, but the atmospheric air 

 which is always impregnated with more or less hygrometric moisture 

 serves to set up the action of the battery by giving up sufficient 

 moisture to wet the surface of the sodium, so that a very thin film of 

 fluid (a solution of soda), is thus interposed between the sodium and 

 electro-negative element, and the internal resistance is very small' in 

 consequence of the thinness of the film of fluid. The sodium is 

 used in the form of plates, conveniently about a quarter of an inch 

 thick, and the plates of carbon, of which one is placed on each side of 

 the sodium, a little longer and about the same thickness as the 

 sodium; these plates, carbon, sodium, carbon, are kept together by 

 means of vulcanised rubber bands, and suspended vertically, a vessel 

 being placed underneath to receive the soda solution as it forms. 



