ilAGNETO-OPTIC PHEN'OMEN'A OF TKON", NICKEL, AND COBALT. 
127 
intensity of magnetisation, the agreement must Ije considered as a very satisfactory 
vindication both of the theory and of the experiments. 
Conclusion. 
31. The various results obtained in this paper do not, I think, require any detailed 
comment. They may be fairly claimed to shew a remarkably good agreement between 
theory and experiment, a better agreement, I believe, than is shewn in the papers of 
Golphammer and Drude, The only considerable discrepancy arises in connexion 
with the original Kerr experiments ; but here it is to be remembered that the 
experiments of Kerr, and those of Sissingh and Zeeman, are not measurements of 
different phenomena, but ore different ways of measuring the same phenomenon. 
Hence any theory that agrees with one of these sorts of experiments ought to agree 
equally well with the other sort; and if this is found not to be the case it is probably 
not the fanlt of the theory, but must be attributed to inaccuracy in one of the sets 
of experimental results. Thus it would appear that the original experiments of 
Kerr, who was the pioneer in this subject, have been (piantitatively much improved 
on by later investigations. 
