^2 Mr Connell on a Froducthfi of Naphthaline. 



heated in a tube, it gave off at a moderate temperature a little 

 naphthaline, which condensed in the upper part of the tube, and 

 as the heat was increased, a yellow fluid condensed on the sides 

 of the tube, which was to a great extent soluble in alcohol. 



Several views may be taken of the mode of production of the 

 naphthaline in the gas apparatus. We might suppose that it 

 had been formed during the destructive distillation of one or 

 both of the oils employed and deposited in crystals at the time 

 of its formation ; but this view is opposed by the circumstance, 

 that no naphthaline was observed whilst the gas apparatus was 

 in operation : and it is also improbable, that crystals of the size 

 obtained and so well defined, should have remained during so 

 long a period in a situation to which there was access of air, 

 when the great volatility of naphthaline is considered. We may 

 conceive, in the next place, that the naphthaline, after it had 

 been formed by a new arrangement of elements during the des- 

 tructive distillation of the oil, was condensed along with some of 

 the other products and held dissolved by them, until the solvent 

 was decomposed or dissipated by the slow operation of time and 

 the external air. Or, lastly, we may suppose that it was not 

 formed during the distillation, but first existed only through the 

 slow and spontaneous decomposition of some of those products, 

 with access of air, after the apparatus had been laid aside. The 

 last view is perhaps on the whole the most probable. 



The influence of external air in the production, or at least 

 development, of naphthaline, has been lately observed by M. 

 Laurent, who found that naphthaline was not obtained in all 

 cases by the distillation of coal tar, and that its production was 

 most certain when the coal tar had been long exposed to the 

 air*. M. lleichenbach did not succeed at all in getting naph- 

 thahne by the distillation of coal tar, but the tar employed by 

 him had been apparently recently prepared +. M. Laurent al- 

 so found that the action of atmospheric air was superseded by 

 that of chlorine. 



• Annales de Chimie et de Physique, xlix. 220. 

 t lb. xlix. 3fi. 



