310 Dr. Faraday's Researches in Electricity. [Series xix. 



(2151. 2176.), but with no other result than that due to the 

 mutual action of the magnetic lines of light, already described 

 in this paper. 



2219. A polarized ray and electric currents were combined 

 in every possible way in electrolytes (951-954). The sub- 

 stances used were distilled water, solution of sugar, dilute sul- 

 phuric acid, solution of sulphate of soda, using platinum elec- 

 trodes; and solution of sulphate of copper, using copper elec- 

 trodes; the current was sent along the ray, and perpendicular 

 to it in two directions at right angles with each other ; the ray 

 was made to rotate, by altering the position of the polarizing 

 mirror, that the plane of polarization might be varied; the 

 current was used as a continuous current, as a rapidly inter- 

 mitting current, and as a rapidly alternating double current of 

 induction; but in no case was any trace of action perceived. 



2220. Lastly, a ray of polarized light, electric currents, and 

 magnetic lines of force, were directed in every possible way 

 through dilute sulphuric acid and solution of sulphate of soda, 

 but still with negative results, except in those positions 

 where the phaenomena already described were produced. In 

 one arrangement, the current passed in the direction of ra- 

 dii from a central to a circumferential electrode, the contrary 

 magnetic poles being placed above and below; and the ar- 

 rangements were so good, that when the electric current was 

 passing, the fluid rapidly rotated; but a polarized ray sent 

 horizontally across this arrangement was not at all affected. 

 Also, when the ray was sent vertically through it, and the eye- 

 piece moved to correspond to the rotation impressed upon the 

 ray in this position by the magnetic curves alone, the superin- 

 duction of the passage of the electric current made not the 

 least difference in the effect upon the ray. 



% iii. General considerations. 



2221. Thus is established, I think for the first time*, a 



* I say; for the first time, because I do not think that the experiments of 

 Morrichini on the production of magnetism by the rays at the violet end of 

 the spectrum prove any such relation. When in Rome with Sir H. Davy 

 in the month of May 1814, 1 spent several hours at the house of Morrichini, 

 working with his apparatus and under his directions, but could not suc- 

 ceed in magnetising a needle. I have no confidence in the effect as a 

 direct result of the action of the sun's rays ; but think, that when it has 

 occurred it has been secondary, incidental, and perhaps even accidental ; 

 a result that might well happen with a needle that was preserved during 

 the whole experiment in a north and south position. 



January 2, 1846. — I should not have written "for the first time" as 

 above, if I had remembered Mr. Christie's experiments and papers on the 

 Influence of the Solar Rays on Magnets, communicated in the Philoso- 

 phical Transactions for 1826, p. 219, and 1828, p. 379.— M.F. 



