1^00 Miscellaneous Intelligence. 



to the electricity in traversini^ the fluid in the cells of the pile and 

 the different conductors which carry it to the experimental wire 

 could be taken into account. — Bull. Univ. A. x. 59. 



2. Conducting Power of different Fluids for Voltaic Electricity. — 

 The following table is drawn up from the experiments of M. 

 Foerstemann. The first column of fijrures indicates the specific 

 gravity ; the second, the quantity of electricity conducted by the 

 different substances in equal times; and the third, the time required 

 for the conduction of equal quantities of electricity. 



Kastner's Archiv. iv. 82. B71II. Univ. A. x. 49, 



3. Influence over the electric Powers of Metals. — In addition to the 

 cases which have been pointed out by Avogadro, Marianini, De la 

 Rive, and others, of a change produced in the electric powers of 

 metals by various circumstances, the following striking one by Van 

 Beek may be quoted. A plate of copper and a plate of iron con- 

 nected by a platina wire were immersed separately in two vessels 

 containing sea water, the portions of fluid being communicated by 

 moistened cotton. Things were left in this state for forty-seven 

 days, during which time of course the copper underwent no change ; 

 after that period, the platina wire was cut, and it was then expected 

 that the copper would be corroded, as will happen to a plate of 

 copper put in the ordinary manner into sea water for a single day 

 only. This effect however did not take place ; the copper remained 

 bright, and the liquid clear, against all expectation, even though the 

 cotton also was removed, and continued so after twenty days. This 

 effect was not because the water had lost its power, for a portion of 

 it, in w^hicli a, piece of ordinary copper had been immersed, caused 

 corrosion in a single day ; and the copper itself being put into an- 

 other portion of sea water, was instantly attacked by it. Hence it 

 appears that the preservation of the copper for so long a time 

 without action on the sea water must have been due to the mutual 

 condition of the metal and solution, induced under the previous cir- 

 cumstances of an existing electric current, and not altogether to a 

 change cither in the one or the other. — Bib. Univ.., Mars, 1828. 



4. Onihe secondary Piles of Rilier. — A long experimental memoir 



