THE 

 LONDON, EDINBURGH, and DUBLIN 



PIIILOSOPIIICAL MAGAZINE 



AND 



JOUENAL OF SOIEXCE. 



♦ ■ 



[FIFTH SERIES.] 



AUGUST 1877. 



XL On Chemical Clasdfication. Bi/ M. M. Pattison Muir, 

 F.R.S.E., Assistant Lecturer on Clieniistrjj, TJie Owens Col- 

 lege, Manchester *. 



1. '^ T) Y the classification of any series of objects is meant 

 J-^ the actual or ideal arrangement together of those 

 which are like and the separation of those which are unlike, 

 the })arpose of this arrangement being, primarily, to disclose 

 the correlations or laws of nnion of properties or circumstances, 

 and, secondarily, to facilitate the operations of the mind in 

 clearly conceiving and retaining in the memory the characters 

 of the objects in question. "f. 



In the classification of a series of objects we wish to discover 

 the deepest and most general resemblances which hold good 

 between these objects ; we do not wish for mere arbitrary de- 

 finitions. In a perfect system of classification, each class of 

 objects must be distinguished from all other classes by some 

 quality or qualities admitting of accurate definition ; these qua- 

 lities, or at least one of them, must be of comparatively easy 

 recognition ; and, further, these properties must be really 

 correlated with every member of the class ; that is, each and 

 every property must exist in each individual of the class. 



The advantages of such a classification are apparent. Given 

 a new object, by inspection or experiment we discover that 

 this object possesses one of the more marked characteristics of 

 a certain class ; we therefore infer that it possesses the remain- 

 ing characteristics of this class : hence we at once learn a great 



* Comuiunicated by tlie Author. 



t W. Stanley Jevons, modifying tlie words of Huxley, ' Principles of 

 Scii'nce,' vol. ii. p. .']48. 



Fhil Mag. S. 5. Vol. 4. No. 23. Aug, 1877. G 



