

THE INTERNATIONAL 



JOURNAL OF MICROSCOPY & NATURAL SCIENCE: 



THE JOURNAL OF THE POSTAL MICROSCOPICAL SOCIETY. 



" Knowledge is not given us to keep, but to impart ; its worth 



is lost in concealment.''^ 



[The Editor does not hold himself responsible for the views of 

 the authors of the papers published.] 



4>- 



Ipreeibential Hbbreee* 



IPolarieeb Xigbt anb its HppUcatione to 



tbe fIDicroacope. 



Presidential Address by G. H. Bryan, M.A. 



Part I. 



N a recent occasion, Lord Kelvin (or rather Sir 

 William Thomson, for he had not then risen to the 

 rank of a " scientific peer "), in the course of a highly 

 interesting lecture on " Motivity," remarked, with 

 reference to the Second Law of Thermodynamics, 

 that he would not attempt to explain the law that 

 evening, "for," as he said, "it could not be 

 explained satisfactorily with less than six hours of 

 tutorial instruction." Now, the same thing is true 

 of polarised light, but with this difference, that to explain t/iat 

 thoroughly, about twelve hours of " tutorial instruction " would be 

 about the minimum. In the short space at my disposal, it will not 



International Journal of Microscopy and Natural Science. 

 Fourth Series. Vol. III. b 



