ques. 5 
XXXI.—On the Constitution of Anthracene or Paranaphthaline, and some of its 
Products of Decomposition. By Tuomas AnpERson, M.D., F.R.S.E., Professor 
of Chemistry in the University of Glasgow. 
(Read 29th April 1861.) 
The solid compounds of carbon and hydrogen form a class of substances to 
which chemists have scarcely, as yet, paid that attention which their importance 
and interest appear to merit. With the exception of naphthaline, very little is 
known regarding them, and it is remarkable that the numerous and varied 
products of decomposition obtained from that singular substance should not have 
induced a more minute examination of the kindred compounds, whose existence 
has been indicated by different chemists. The interest attaching to these com- 
pounds is all the greater because, according to their discoverers, several of them 
are isomeric, or at least polymeric, with naphthaline ; and a more careful exami- 
nation of them might be expected to throw some light on their intimate consti- 
tution, and relations to that body. 
Not less than five substances said to be polymeric with naphthaline have - 
been described. These are paranaphthaline or anthracene, metanaphthaline or 
retisterene, pyrene, and two substances not yet named, which occur along with 
benzine and benzophenone among the products of the destructive distillation of 
benzoate of lime, and are apparently quite distinct from one another and the 
other three. All of these substances, except naphthaline, have hitherto been 
obtained in small, and some of them in very minute quantity, so that their con- 
stitution has been in most instances fixed by analysis alone; and the difficulties 
attending the analysis of highly carbonaceous compounds at the time they were 
made, as well as the absence of any control derived from the examination of 
their products of decomposition, have naturally occasioned some doubts as to the 
accuracy of the formule assigned to them. 
Paranaphthaline or anthracene, which was discovered by Dumas and LauRENT 
in the year 1832,* is the only one of these substances whose examination has 
extended beyond the mere analysis; and the determination of its vapour density 
by the former chemist gave for it the formula C,, H,,, which the examination of 
some of its decomposition products by the latter was supposed to confirm. A 
critical examination of LAURENT’s experiments by no means bears out this 
opinion. They are in many respects extremely imperfect, have obviously been 
* Annales de Chemie et de Physique, vol. 1. p, 187. 
VOL. XXII. PART III. 8P 
