420 Miscellaneous Intelligence. 



perpendicular to the dipping needle, ascends and descends in 

 these directions. In order to ascertain the existence of this 

 effect, I bent a wire twice at right angles, as in the first expe- 

 riment described in this note, and fastened on to each extremity 

 a short piece of thin copper, wire amalgamated, and made the 

 connexion into the basins of mercury by these thin wires. The 

 wire was then suspended, not as before, from the ceiling, but 

 from a small and delicate lever, which would indicate any ap- 

 parent alteration in the weight of the wire ; the connexions 

 were then made with the voltaic instrument, but I was surprised 

 to find that the wire seemed to become lighter in both direc- 

 tions, though not so much when its motion was towards the 

 south as towards the north. On farther trial it was found to 

 ascend on the contacts being made, whatever its position to the 

 magnetic meridian, and I soon ascertained that it did not de- 

 pend on the earth's magnetism, nor on any local magnetic ac- 

 tion of the conductors, or surrounding bodies, on the wire. 



After some examination I discovered the cause of this un- 

 expected phenomenon. An amalgamated piece of the thin 

 copper-wire was dipped into clean mercury, having a stratum 

 of water or dilute acid over it; this, however, was not neces- 

 sary, but it preserved the mercury clean and the wire cool. In 

 this position the cohesive attraction of the mercury raised a 

 little elevation of the metal round the wire of a certain magni- 

 tude, which tended to depress the wire by adding to its weight. 

 When the mercury and the wire were connected with the poles 

 of the voltaic apparatus, this elevation visibly diminished in 

 magnitude by an apparent alteration in the cohesive attraction 

 of the mercury, and a part of the force which before tended to 

 depress the wire was thus removed. This alteration took place 

 equally, whatever the direction in which the current was passing 

 through the wire and the mercury, and the eflect ceased the 

 moment the connexions were broken. 



Thus the cause which made the wire ascend in the former 

 case was evident, and by knowing it, it was easy to construct 

 an apparatus in which the ascent should be very considerable. 

 A piece of copper bell-wire, about two inches ]ong,]iad portions 

 of the amalgamated fine copper-wire soldered on to its ends, 

 and those bent downwards till parallel to each other. This 

 was then hung by a silk thread from the lever, and the line 

 wire ends dipped into two cups of clean mercury. When the 

 communications were completed from the voltaic instrument 

 through these two cups, the wires would rise nearly an inch out 

 of the mercury, and descend again on breaking the communi- 

 tion. 



Thus it appears that, when a fine amalgamated copper-wire 

 dips into mercury, and a current of voltaic electricity passes 

 through the combination, a peculiar eflect is produced at the 



