198 Miscellanies. 



that a tolerable good battery may be made of one metal only, viz. 

 zinc, provided one of the plates much exceeds the other in size, and 

 the sulphate of copper be used as the exciting liquid. To construct 

 a battery of this description, a number of narrow strips of sheet zinc, 

 arranged in the form of a cylinder, are immersed in a cylinder of. 

 zinc containing a solution of the sulphate or nitrate of copper ; the 

 zinc strips answering merely for conductors. 



Among other discoveries lately made by Dr. Page in relation to 

 this subject, we notice the production of sparks and shocks from a 

 thermo-electric apparatus, consisting of a pair of bismuth and anti- 

 mony plates heated by a spirit lamp. This condition has hitherto 

 been wanting to establish fully the identity of thermo-electric, with 

 common galvanic currents. — Salem Observer. 



13. Animal Electricity; by MM. Linari and Matteucci. — The 

 five helices employed by M. Linari, contained five hundred and sev- 

 enty seven metres of copper wire. Two had the ordinary form ; 

 the three remaining were composed of the wire wound round spirally 

 in a plane, and had a square perimeter. Through one of these heli- 

 ces was passed a cylinder of iron, 0" 635 long, and 0"' 31 in diame- 

 ter. This system of helices was connected and terminated by two 

 plates of silver, provided each with an isolating handle. The circuit 

 was interrupted by cutting the wire between the last helix and one of 

 the plates of silver, in order to insert the extremities of the wire 

 into a vessel of mercury and thus amalgamate them. 



The experiment was performed as follows : the torpedo wiped 

 dry, was placed on a plate of glass, with one of the pieces of silver 

 upon his back and the other on his belly. The animal was then 

 irritated by striking him with one of the plates on his tail and gills, 

 and was thus induced to discharge himself. After several trials, 

 M. Linari succeeded in obtaining a spark, which appeared between 

 the mercury and the wire. By touching together the amalgamated 

 wires out of the mercury, he succeeded in obtaining a succession of 

 brilliant sparks. He observed no difference in the capabilities of 

 torpedoes of different sizes to produce this result. A small one of 

 four inches in diameter afforded a long succession of bright sparks. 



The decomposition of acidulated water, and a durable magneti- 

 zation of a steel needle were invariably obtained by M. Linari. 



M. Matteucci employed in his experiments similar apparatus to 

 ihat of Linari, containing however only three hundred metres of 



