Intelligence and Miscellaneous Articles. ' 5S9 



"13. Irise a la surface, cristaux aplatis, disposes en forme de bou- 

 quet, sur quarz amorphe ; mine Beschertgliick, Freyberg. 



** 14. Rouge fonce, jietits cristaux, avec d'autres d'un rouge clair 

 qui ofFrent aux soramets les faces du rhombo'ide primitif, avec cbaux 

 carbonatee dodecaedre raccourcie, sur fer sulfure magnetique ; mine 

 Churprinz." 



We trust we have now exhi])ited sufficient proofs of the value of 

 this work, and we again repeat our opinion that it will prove highly 

 useful to the cultivators of Mineralogical Science, and it must, we 

 think, accompany every collection of the slightest degree of import- 

 ance. 



LXXXI. Intelligence and Miscellaneous Articles. 



ON THE ELECTRICAL CURRENTS PRODUCED DURING THE PRO- 

 CESSES OF FERMENTATION AND VEGETATION. BY MR. JAMES 

 BLAKE, MEDICAL STUDENT, UNIVERSITY COLLEGE, LONDON. 



BEFORE describing the experiments I have made on this subject, 

 I shall relate the manner in which I arranged the apparatus in 

 order to detect any electrical currents which I expected would be 

 produced during the decomposition of the sugar. Having observed 

 that during the earlier stages of fermentation the yeast remains in 

 a layer on the bottom of the vessel, I placed a disc of platinum at 

 the bottom of the vessel and another disc in contact with the surface 

 of the liquid ; these were connected to platinum wires, which were 

 again soldered to copper wires serving to connect them with the 

 galvanometer. The wire in connection with the lower disc of 

 platinum was passed through a glass tube closed at the bottom so 

 as to prevent its being in contact with the upper portion of the 

 fluid. The vessel was of earthenware and contained about 3^ gal- 

 lons. 



The galvanometer contained 360 coils, the needles forming an 

 almost astatic arrangement, and weighing, together with the wire 

 which connects them, 2 grs. For convenience of reference I shall 

 call the wires which connect the platinum in the fluid with the gal- 

 vanometer b and c respectively ; the former being attached to the 

 lower, and the latter to the upper disc. The apparatus being ar- 

 ranged, and the jar containing wort in which the process of fermen- 

 tation had lately commenced, I found on connecting the wires c and 

 b by means of the galvanometer, that a current of electricity passed 

 through it, which entered by the wire c, indicating that the upper 

 part of the fluid was positive in relation to the lower. I allowed 

 the wires to remain, in order to see if any change took place either 

 in the quantity or direction of the current, during the subsequent 

 stages of fermentation. For this purpose I made observations from 

 time to time, and found, for some hours after the process of fer- 

 mentation had commenced, a gradual increase in the quantity of 

 electricity set in motion ; after a certain time this arrived at a maxi- 

 mum, and then gradually decreased, until no indication of a current 

 was afforded. In a short time, however, a deflection of the needle 

 was again produced, but in an opposite direction. This also gra- 



