EXTENDED TO DENSE BODIES. 587 



Every sort will soon proceed to dilferentiate itself, in spite of every process 

 which aims at obtaining it in a homogeneous state. The products of the most 

 careful fractional distillation probably continue to be what they are found to be 

 only for a short time. Some of these give exquisitely constructed molecules, as 

 for instance the distillate lately obtained by MM. Cahoues and Pelouse from the 

 rock-oil of America. Its formula is 0^2^!^^, which doubling, we obtain C^Ji.^^., 

 plainly indicating, a dodecatom whose body is composed of naphtha with double 

 walls, and whose poles are atoms of marsh gas. Whence we can understand the 

 permanency of rock-oil in the presence of moisture and oxygen ; for it is on the 

 poles that chemical action mostly takes place ; and marsh gas (for a reason which 

 may be shown) is in all natural conditions secure from the attack of oxygen. 

 Moreover, this beautiful hydrocarbon seems to have succeeded in the hands of 

 its discoverers in gaining its way up to icosatomic molecules, each occupying no 

 less than 16 normal volumes. Thus, — 



Distillate of Rocl-oil . Q^lgag^H V'C.H.),.^ j880j_»60^.^^^ .^^^ 



16AQ 16 X 324 ^ 



Many may be the molecular types developed by the reduction of the 

 naphthas, especially by the departure of hydrogen in greater quantity than car- 

 bon, and the introduction of nitrogen and oxygen instead. The most highly parti- 

 tioned, and the last which admits of being raised into the aeriform state, and thus 

 separated from the carbonaceous residuum and brought before the chemist, is an 

 element consisting of a single atom of H surrounded by five of C with an atom 

 of H on one pole, to carry it up. Its elementary formula is consequently CgH^. 

 But it is dissymmetrical. And in the aeriform state, with a normal or atmo- 

 spherical volume it must be Cj^^H^ ; and with a double volume, like most com- 

 pounds, it must be C2oHg. It is therefore the naphthalinic element. As the 

 terminal of one pole is H and of the other C, we may well infer that it is capable 

 both of the icosatom and the dodecatom. These give, — 



"^AQ^'^ ^^394^^ ^-^'-^^^- ^^P*- ^"^^^ (Reichenbach.) 

 Naphthaline . G= | Mean 1-035. Expt. 1-048 (Ure.) 



(C,H2)2o_ 600 + 40 _ 

 V 2AQ ~ 2x324 ~ '' 



If heat were gently applied and sufficient time given, and means of purification 

 existed, it looks as if, between naphtha and naphthaline, there might be obtained 

 the essential oils ; for their element is a combination of the type of marsh gas 

 with that of naphthaline with omission of the atom of H on the pole of the latter, 

 ' which causes its dissymmetry. Or, the essential oil element is marsh gas CHHgC 

 = C2H^ with (CH)3, substituting Hg. But 3CH may be variously applied so as 



