682 PROFESSOR T. ANDERSON ON THE 
made on avery small quantity of material, and the formule (mostly deduced 
from a single analysis) are so improbable, that there can be but one opinion as to 
the necessity for submitting the subject to a further investigation. 
Anthracene, as is well known from the observations of Dumas and LAURENT, 
is met with only among the latter portions of the distillation of coal-tar. It has 
been little seen by chemists, because hitherto the distillation has not generally 
been pushed so far as to yield it in quantity ; but during the last few years, the 
demand for the asphalt and the higher oils having increased, the distillation has 
been carried further, and it has been found abundantly in some of the products, 
and even been used in the manufacture of machinery grease. I have availed my- 
self of the opportunity which a large supply afforded of extending the examina- 
tion of anthracene, and with the result of showing that its constitution differs 
from that attributed to it by its discoverers, and that it is not polymeric with 
naphthaline. 
Before entering on the details of my own experiments, it may be advisable to 
recapitulate shortly the history of the substance. As already stated, it was 
discovered by Dumas and Laurent, working in concert, in 1832, and described 
by the former chemist, who attributed to it the formula C,, H,,, with which his 
results corresponded very closely. In 1835 Laurenr* described, under the name 
of paranaphthalese, a compound for which he gives the formula C,, H, O,, and he 
appears to have considered it to be a direct product of the action of nitric acid on 
anthracene. In a subsequent paper} he extends his investigation in this direc- 
tion, and describes no less than five different nitro-compounds, and assigns to 
them very problematical formule. In this paper he again refers to paranaph- 
thalese, but under the name of anthracenuse, giving for it the formula C,, H, O;, 
and stating that it is not a product of the direct action of nitric acid on anthracene, 
but formed by the decomposition of a nitro-compound, in a manner precisely 
similar to that in which naphthase is obtained from nitronaphthaline. He men- 
tions that a substance of similar properties is obtained from several of the nitro- 
compounds he prepared, but leaves it an open question whether it is in all cases 
the same, or whether it differs in constitution according to the nitro-compound 
from which it is produced. He also describes a chlorine substitution product, 
and adopts the name of anthracene ; a change even then advisable, and which the 
results of my investigation show to be quite indispensable. 
Crude anthracene is in the form of a soft yellow mass, not unlike palm oil, but 
with a greenish tinge and harder consistence; in this state, it contains a little 
naphthaline and a considerable quantity of oil of high boiling point, which causes 
it to leave a greasy stain on paper, and to melt easily when rubbed between the 
fingers. It has a decided though not a strong smell, due partly to the naphthaline, 
* Annales de Chemie et de Physique, vol. lx. p, 220. t Ibid., vol. Ixxii. p. 415. 

