40 Observations on Mr,Munay^s Paper on the [Jan. 



poles of two bar magnets ; when it became speedily plumed 

 with crystals of silver.'^ 



•' A portion of the same wire was snapped in twain, and the 

 magnet passed over one of the fragments, and both projected 

 into solution of nitrate of silver. That which was magnetized 

 reduced the silver, while the other remained inert." 



I divided a dilute solution of nitrate of silver into three portions. 

 In one I placed a steel bar hardened at the ends, but which did 

 not attract iron filings, and consequently was not magnetized. 

 In the two other solutions of nitrate of silver, I put magnets 

 formed of similar bars, the north pole of one, and the south pole 

 of the other, being immersed, their opposite poles projecting 

 above the edges of the glasses containing the solutions ; the 

 poles were then connected by an unmagnetized steel wire. 

 Several hours elapsed before any sensible precipitation occurred 

 in either of the three glasses ; at length a few fine brilhant flakes 

 of metalhc silver appeared in all of them, and I did not observe 

 that they were formed sooner in one solution than the others. 

 These flakes increased very slowly, till a certain quantity had 

 collected, when the action increased rapidly, and an abundant 

 precipitate of reduced silver was collected in each of the three 

 glasses. I could perceive little or no difference in the quantity 

 of the silver thrown down, or in any other respect, the results in 

 the three solutions being as nearly similar as possible, excepting 

 that from some unknown cause the unmagnetized bar was much 

 more deeply corroded at the part in contact with the surface of 

 the fluid. The increase of action after a certain quantity of 

 silver had been precipitated, was probably owing to the contact 

 of the metalhc precipitate and the iron. 



It is evident from these experiments that magnetism has no 

 power whatever in modifying, increasing, or reversing the mutual 

 action of steel and solution of nitrate of silver. Indeed it is so 

 well an established fact, that iron precipitates silver from its 

 solution in nitric acid, that it is quite unaccountable how it 

 should have escaped Mr. Murray's knowledge both from reading 

 and experiment. The following authors distinctly mention that 

 silver is precipitatea from its solution by iron. Newmann, 

 Chemistry, page 47 ; Murray, vol. iii. p. 212, fourth edit. ; The- 

 nard, vol. ii. p. 314, second edit. 



If magnetism were really capable of decomposing metalHc 

 salts, it would probably reverse the order of affinity, as occurs 

 in voltaic combinations, when copper is precipitated on silver 

 wire rendered negative by the battery. I, therefore, immersed 

 two magnets connected by a steel bar in two separate glasses 

 containing solutions of sulphate of zinc, the arrangement being 

 just the same as that of the magnets in the solutions of nitrate 

 of silver ; not the least precipitate was produced in either, nor 

 in a third solution of sulphate of zinc containing an unmag- 

 netized bar ; the only observable effect was, that the bars were 

 all shghtly tarnished. 



