4. On ike Influence of Magnetism on Molecular Arrangement. 



capable of supporting fifty pounds when connected with a 

 single galvanic pair excited by water acidulated with sulphu- 

 ric acid. On pouring a warm and tolerably strong solution 

 of nitrate of mercury into the trough, there was immediately 

 formed over the surface a series of beautifully regular curves 

 from pole to pole, as shown in fig. 6, which also represents 

 the arrangement. 



11. A similar glass trough, filled with a moderately strong 

 solution of the nitrate of mercury, was supported on the poles 

 of the same electro-magnet, connected with a small battery of 

 a more permanent, but less powerful arrangement, and all was 

 allowed to remain at rest until crystallization had taken place. 

 The result was similar to that already described (9.), but 

 much more strikingly shown. The order of arrangement 

 taken by the crystals is shown in Plate II. fig. 7. 



12. A plate of copper with an edging of wax was placed on 

 the electro-magnet in the same manner as the glass plate; 

 over it a very weak solution of nitrate of silver was quickly 

 poured; the plate immediately blackened from the decompo- 

 sition of the silver salt by the copper. In about a minute the 

 finely divided silver arranged itself into curves, as represented 

 in fig. 8, which were after a few minutes again destroyed. By 

 using a sheet of chemically-pure copper, obtained by electro- 

 type deposit, I found a permanent impression of these curves 

 could be obtained, owing to the oxidation of the copper along 

 the spaces, which the finely divided silver, when distributed in 

 curve-lines, did not cover. 



13. A plate of hard copper, such as is used by engravers, 

 was placed in precisely the same circumstances, and covered 

 with a tolerably strong solution of nitrate of silver. It was 

 left in contact with the electro-magnet for a night. On wash- 

 ing off the deposit of silver which covered it, it was found that 

 the acid of the silver salt had bitten deeply into the plate over 

 an oval space around the poles, leaving a small space between 

 them quite bright. The copper over this etched space was 

 covered with an immense number of minute holes; and be- 

 yond this the oxidation of the surface had proceeded in 

 curved lines, as represented in fig. 9. We thus have perma- 

 nent evidence of the influence of magnetic force in determi- 

 ning chemical action. 



14. Into one of the glass troughs before named, placed on 

 the electro-magnet, a weak solution of nitrate of silver was 

 poured, and into this an equally weak solution of sulphate of 

 iron. In about five minutes precipitation of silver commenced ; 

 this precipitate arranged itself over the glass in curves pro- 

 ceeding from and around the poles in the same manner as it 



