82 Magnetic Galvanism 



to' 



the mouth, and they are invariably accompanied by strong flashes of 

 light and an acid taste. The increase of effect, owing to the rapid 

 sliding off of the keeper, may, in this way, be rendered very appar- 

 ent, for the shock, at times, equals that produced by a powerful gal- 

 vanic battery. A sheet of paper interposed between the keeper and 

 magnet, diminishes the effect, much more than a metallic plate of 

 greater thickness. 



The magnet, by its connection with the coil, acts a far more im- 

 portant part than as a conductor for the fluid. For the purpose of 

 giving slight shocks and the galvanic taste, this connection, it is true, 

 may be destroyed by separating the wire h from the magnet — all 

 that is necessary is to put the ends, h and a, of the coil, into the 

 mouth and to slide off the keeper. These wires will even impart 

 the acid taste by simply rocking the keeper upon the poles of the 

 magnet, yet no sparks appear between these parts until the connec- 

 tion between h and the magnet is restored, and, at the same time, 

 the most obvious increase of shock, flashes of hght, &;c. will be ex- 

 perienced. It is not a little remarkable, however, that this connec- 

 tion between the coil and magnet, wholly destroys the strong galvanic 

 taste of the connecting wires, occasioned by rocking the keeper upon 

 the magnet. 



Direction and force of the galvanic current, as indicated by the 

 galvanometer. — One can scarcely refrain, after having experienced 

 the effects described in this communication, from entertaining the 

 conviction, that the magnet, thus remarkable for its development of 

 galvanism without tlie intervention .or aid of chemical action, will ere 

 long furnish the philosopher with a powerful and novel instrument of 

 analysis; yet, it must be confessed, that its action upon the galvano- 

 meter is quite insignificant, when compared with the smallest sized 

 elementary battery, exposed to weak acids. The galvanometer em-, 

 ployed, was an inferior one, consisting of a single needle and only 

 seven coils of stout copper wire, yet it obeyed readily the impulse 

 given by plates of zinc and copper, not larger than an inch in diam- 

 eter. My first experiments were made with a coil of about thirty 

 yards on the keeper, and, although I distinctly felt the shock, at dif- 

 ferent times, through the' galvanometer, I never could perceive more 

 than a tremulous motion of the needle. By substituting, for this 

 latter instrument, a large spool, (fig. 3,) filled with silk-bound copper 

 v/ire, (about one hundred yards,) the two ends turning out and cou- 

 sj£i3ted with the coil on the keeper, by means of the wires a, b, I was 



