140 Intelligence and Miscellaneous Articles, 



2. " On Further Evidence of Endothiodon bathy stoma (Owen) 

 from Oude Kloof, in the Nieuwveldt Mountains, Cape Colony." By 

 Prof. H. G. Seeley, F.K.S., F.G.S. 



3. " On the Discovery of Mammoth and other Bemains in 

 Endsleigh Street, and on Sections exposed in Endsleigh Gardens, 

 Gordon Street, Gordon Square, and Tavistock Square, N.W." By 

 Henry Hicks, M.D., F.R.S., Secretary of the Geological Society. 



4. "The Morphology of StepTianoceras zigzag." By S. S. 

 Buckman, Esq., F.G.S. 



XV. Intelligence and Miscellaneous Articles. 



EXPERIMENTS ON ELECTROLYTIC POLARIZATION. 

 BY L. ARONS. 

 TF a cell containing dilute sulphuric acid through which a current 

 -*- is passed by means of platinized electrodes is divided into two 

 halves by a partition of one of the noble metals platinum, gold, or 

 silver, so that all the lines of flow must traverse the metal, an en- 

 feeblement of the current, in general, occurs. On that side of the 

 partition which is opposite the anode hydrogen polarization occurs, 

 and on the opposite side oxygen polarization. The true resistance 

 of the cell is not appreciably altered, if the thickness of the metal 

 is very small compared with the length of the cell of liquid. The 

 question suggests itself whether the metal partition can be made 

 so thin that the electrical polarization on either side will neutralize 

 the action of that on the other. I have in fact succeeded in 

 observing this phenomenon. 



The cell, 22 cm. long, 5 cm. broad, and 8 cm. high, was divided 

 into two halves ; a hole 1*5 cm. in diameter was bored in the 

 plate, which could be easily removed and replaced by exactly similar 

 ones in which the aperture was filled with plates oi different 

 metals. The cell formed in the first place part of a circuit with 

 a galvanometer and a battery of 2 to 5 accumulators. If, instead 

 of the plate with a free aperture, one was used which was closed 

 bv platinum foil 0*1 mm. in thickness, the deflexion of the gal- 

 vanometer became considerably less, and on both sides there was 

 a considerable disengagement of gas. The aperture of a second 

 plate was closed by gold-leaf fastened by canada balsam. If this 

 plate was substituted for that with a free aperture, the deflexion 

 of the galvanometer remained unchanged and there was no visible 

 trace of disengagement of gas. The result was the same when 

 silver was used instead of gold-leaf. It might be supposed that 

 the current did not at all traverse the metal leaf, but that minute 

 holes in it formed a path for the current. No such holes could, 

 however, be perceived in the layers used ; they could therefore be 

 only microscopic if they at all existed, and the sum of their sections 

 must be infinitely small in comparison with the surface of the 

 metal. But openings of even considerable size could not 



