THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



DECEMBER 1874. 



LVI. On the Relations between Affinity and the Condensed Sym- 

 bolic Expressions of Chemical Facts and Changes known as Dis- 

 sected (Structural) Formula. By C. R. Alder Wright, D.Sc. 

 (Lond.), Lecturer on Chemistry in St. Mary's Hospital Medical 

 School*. 



1. "FN a paper published in the Philosophical Magazine in 

 J- April 1872, attention was called to the meanings attached 

 to and the facts summed up in modern chemical formulas, and to 

 some of the connexions and distinctions between these pithy sum- 

 maries of knowledge and certain hypotheses assumed by che- 

 mists to account for the observed facts. The present essay bears 

 directly on the former and indirectly on the latter of these points, 

 the primary object being to call attention to the necessity which 

 exists for a full and complete study of the amounts of energy 

 involved in chemical changes- — a subject of which it may be said 

 that as yet we are almost unacquainted with even the faintest 

 outlines of its scope and bearings. 



In the modes of calculation adopted there is little that is new, 

 the author having availed himself largely of the methods of 

 L. Hermannf, Berthelot, Julius ThomsenJ, and others, having 

 simply modified or extended them as occasion served. 



2. Definitions. — When weights w v w 2 , w< 6 , ... of dissimilar 

 forms of matter A v A 2 , A 3 , . . . coalesce so as to give rise to a 

 weight w l + w 2 + w 3 -\- . . . =2 (10) of a single homogeneous body, 

 this single body is said to be a compound of, or to be composed of 



* Communicated by the Author. 



t Chemisches Centralblatt, 1869, Nos. 34 & 35. 



% Berichte der Deut. Chem. Ges. vol. v. p. 769. 



Phil. Mag. S. 4. Vol. 48. No. 320. Dec, 1874. % D 



