294? Dr. Faraday's Researches in Electricity. [Series xix 



of very rapid evaporation generated on those internal liquid 



surfaces which surround one or more bubbles of a gaseous Jluid. 



I am, Gentlemen, 



Your most humble Servant, 

 Ghent, March 2, 1846. F. DoNNY. 



XLIX. Experimental Researches in Electricity. — Nineteenth 

 Series. By Michael Faraday, Esq., D.C.L., F.R.S., 

 Fidlerian Prof. Chem. Royal Institution, Foreign Associate 

 of the Acad. Sciences, Paris, Cor. Memb. Royal and Imp. 

 Acadd. of Sciences, Pelersburgh, Florence, Copenhagen, 

 Berlin, Gottingen, Modena, Stockholm, SfC. fyc* 



§26. On the magnetization of light and the illumination of 

 magnetic lines of force f. 



Tf i. Action of magnets on light. 



2146. Y HAVE long held an opinion, almost amounting to 

 -*- conviction, in common I believe with many other 

 lovers of natural knowledge, that the various forms under 

 which the forces of matter are made manifest have one com- 

 mon origin ; or, in other words, are so directly related and 

 mutually dependent, that they are convertible, as it were, one 

 into another, and possess equivalents of power in their ac- 



* From the Philosophical Transactions for 1846, Part I., having been 

 read November 20, 1845. 



f The title of this paper has, I understand, led many to a misapprehen- 

 sion of its contents, and I therefore take the liberty of appending this ex- 

 planatory note. Neither accepting nor rejecting the hypothesis of an 

 aether, or the corpuscular, or any other view that may be entertained of the 

 nature of light; and, as far as I can see, nothing being really known of a 

 ray of light more than of a line of magnetic or electric force, or even of a 

 line of gravitating force, except as it and they are manifest in and by sub- 

 stances; I believe that, in the experiments I describe in the paper, light has 

 been magnetically affected, i. e. that that which is magnetic in the forces 

 of matter has been affected, and in turn has affected that which is truly 

 magnetic in the force of light: by the term magnetic I include here either 

 of the peculiar exertions of the power of a magnet, whether it be that which 

 is manifest in the magnetic or the diamagnetic class of bodies. The phrase 

 " illumination of the lines of magnetic force " has been understood to imply 

 that I had rendered them luminous. This was not within my thought. I 

 intended to express that the line of magnetic force was illuminated as the 

 earth is illuminated by the sun, or the spider's web illuminated by the 

 astronomer's lamp. Employing a ray of light, we can tell, by the eye, the 

 direction of the magnetic lines through a body; and by the alteration of 

 the ray and its optical effect on the eye, can see the course of the lines just 

 as we can see the course of a thread of glass, or any other transparent 

 substance, rendered visible by the light : and this was what I meant by il- 

 lumination, as the paper fully explains. — December 15, 1845 M.F. 



