THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JUNE 1892. 



LVL Quaternions as a practical Instrument of Physical 

 Research. By Alexander M°Aulay, M.A., Ormond 

 College, Melbourne*, 



IN writing the history of the Mathematics of the 19th 

 century the historian will be brought face to face with a 

 phenomenon hard to account for. 



The inventor of quaternions was one of the greatest, per- 

 haps the greatest, mathematician of this century. His work 

 was varied and far reaching in its effects, but his name was 

 always associated in the mind of the hearer with one well- 

 defined group of his works — his quaternion researches. Thus 

 the subject was brought forth in the full light of day, and has 

 by no means passed into the limbo of forgotten things. Indeed 

 the word " Quaternions " is fully as familiar even with non- 

 mathematicians as the phrase " Cartesian Geometry." 



But in spite of this he has left scarcely a successor. His 

 two huge volumes form far more than half the whole original 

 work that has been done in the subject. And this notwith- 

 standing the fact that he deliberately did not attempt to apply 

 the subject to Physics, although expressing his belief that in 

 other hands it would prove a powerful instrument of research. 



Can any cause be assigned for this extraordinary case of 

 arrested development? The answer that by far the ma- 

 jority of physicists would give as to the physical aspect of 

 the subject is, that the instrument is an admirable one for 



* Communicated by the Author ; having been read before the Austra- 

 lian Association for the Advancement of Science, January 1892. 



Phil May. S. 5. Vol. 33. No. 205. June 1892. 2 K 



