THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



FEBRUARY 1887. 



XI. The Determination of the Constitution of Carbon Com- 

 pounds from Thermochemical Data. By Henry E. 

 Armstrong, F.R.S., Professor of Chemistry, City and 

 Guilds of London Institute Central Institution "*. 



THE past year has witnessed the publication of the 

 fourth and concluding volume of Julius Thomsen's 

 Thermochemische Untersuchungen, an event of high import- 

 ance on account of the magnitude of the work and of the 

 reputation for accuracy which its author enjoys. Indeed the 

 unwearying perseverance and great manipulative skill which 

 have enabled him to accumulate the mass of data now pub- 

 lished in a collected form must excite the admiration and 

 wonder of all who are able to judge of the difficulties to 

 be overcome in the execution of thermochemical determi- 

 nations. 



In the present article I desire to direct attention to the 

 fourth volume, which is wholly devoted to the description of 

 determinations of the heat generated on combustion of no less 

 than one hundred and twenty distinct carbon compounds — 

 members of about twenty different groups, and also to a 

 theoretical discussion of the results and their bearing on 

 received views of the constitution of carbon compounds. As 

 many of the conclusions are directly opposed to, and irrecon- 

 cilable with, popular views, it is desirable that they should be 

 brought more directly under the notice of British chemists, 

 and that the interpretations which Thomsen puts upon his 

 results should be carefully considered and criticised. I may 

 * Communicated by the Author. 



Phil Mag. S. 5. Vol. 23. No. 141. Feb. 1887. G 



