THEORY. 191 
The reason why I suppose a magnetic vibration 
may be induced as well as a chemical or electric 
motion, is obvious, since Morichini and Mrs. M. 
Somerville have shown, by direct experiment, that 
magnetism is induced in steel by exposure to the 
most refrangible of the solar rays, precisely those 
which induce phosphorescence.* Moreover, light 
is engendered by magnetism in a curious experi- 
ment made by Grove in 1845. <A tube, filled with 
the liquid in which magnetic oxide of iron has been 
prepared, and terminated at each end by plates of 
glass, is surrounded by a coil of coated wire. 
“To a spectator, looking through this tube, a 
flash of ight is perceptible whenever the coil is 
electrized ; and less hght is transmitted when the 
electrical current ceases, showing a symmetrical 
arrangement of the minute particles of magnetic 
oxide while under the magnetic influence.” (Cor- 
relat. of Phys. Forces, p. 158.) Some remarkable 
results were likewise arrived at by Sir W. Snow 
Harris, as early as 1834, by vibrating magnets 
in the sun, and published in the ‘ Kdinburgh 
Philosophical Transactions’ for that year. 
A similar conception would apply to phospho- 
rescence produced by heat, chemical action, elec- 
tricity, etc. 
* These are also the rays which cause chlorine to combine 
with hydrogen, and which decompose many chemical com- 
pounds. 
