1822.] Mr. Murray's Reply to B, M. EM 



magnetism, will move in a plane (for so the small part we can 

 experiment on may be considered) perpendicular to the dip of 

 the needle, and in a direction perpendicular to the current o€ 

 electricity passing through it." 



An expectation was entertained, in consequence of this law, 

 that where the dip was small, a difference in the weight of an 

 electro-magnetic wire might be perceived when the current 

 passed through it in different directions. In endeavouring to 

 estimate if the difference were perceptible in these latitudes, a 

 very remarkable effect was observed. On suspending a piece of 

 wire from a lever, and letting very fine wires dip from it into two 

 ^ups of mercury, it apparently became lighter every time the 

 electric current was passed through it either one way or the 

 other. This effect was at last found not to be a real alteration 

 in the gravity of the wire, but to be an affection of the mercury, 

 with which it was in contact. The wires when dipped into the 

 metal drew up a httle elevation around them owing to the cohe- 

 sive attraction of the mercury. On close inspection, it was 

 observed that every time the connexions were completed, these 

 elevations were diminished, so that in fact the wire was lightened 

 of a portion of the weight before attached to it; on breaking the 

 connexions the elevations resumed their original bulk. Hence 

 when electricity passes from a fine wire into mercury, or froa» 

 mercury into a fine wire, an effect is produced equivalent to a 

 diminution of the cohesive attraction of the mercury. Whether 

 it is really such a diminution, or is due to some other cause^ 

 remains to be determined. 



In concluding this imperfect sketch of the labours of Mr. 

 Faraday in this new and interesting branch of science, we 

 earnestly recommend him to continue his researches on a subject 

 which he has so ably illustrated and enriched by discoveries 

 that are in the highest degree curious and important. 



Article X. 



Reply to n, M, By John Murray, FLS. MWS. &c. &c. 

 (To the Editor of the Annals of Philosophy.) 



SIR, Suny Institution, Jan. 12, 1822. 



I AM a stranger to the name which the letters B, M. are pro- 

 posed to adumbrate. If truth be the object of this writer, why 

 does he blush to own it? Is science to be a masquerade, and its 

 friends appear in false or fictitious characters ? An honest man 

 ought to be ashamed of such a contemptible subterfuge — ^' talia 

 fares." It is something to grapple with a noble enemy even 



