442 On the Comlination of Acids 



from it, even by warm alkaline solutions. Yet when it is 

 iublinied, the vessels in which the operation is made be- 

 come strongly acid ', and when, instead of subliming it, it 

 is passed through a red-hot iron tube, a greater quantity of 

 acid is still abstracted from it. Lastly, when decomposed 

 both by concentrated and weak nitric acid, a large quantity 

 of oxy-muriatic acid is produced in the first instance, and 

 in the second much muriatic acid. Relative to that por- 

 tion of liquid derived from the crystalline mass, the weight 

 of which was 20 grammes, it was white, and diffused acid 

 vapours,. but ceased after an exposure of some days to the 

 atmosphere, and was no longer acid ; it crystallized in mass 

 some degrees below zero, and preserved an intimate union 

 with much muriatic acid. 



Thus all my observations, except one only, agree with 

 those of Gchlen. That in which we do not coincide is re- 

 lative to the liquid product of the operation. Gehlen ob- 

 tained It of a brownish-black, and I always obtained it 

 white. This difference, I think, 'depends on Gthlen having 

 used the essence known in commerce, which contains, un- 

 less distilled with great care, a resin, and has then the 

 properly of blackening and forming a large uncrystallizable 

 residue. Neither do I draw from my observations the same 

 theoretical inferences as this chemist does from his. I 

 think that the essential oil of turpentine is not decomposed 

 by muriatic acid, and consequently that these two bodies 

 combined together in certain proportions form concrete 

 camphor; probably the small portion of liquid product ob- 

 tained by him is of the same formation : besides, it is not 

 improbable that the difference existing between the cam- 

 phoric concretion and the liquid product, depends on a 

 small quantity of an ethereal oil mixed with the essence, 

 and capable of forming \yith muriatic acid a liquid product. 

 Lastly, what induces me to believe that the muriatic acid 

 does not decompose the essence, but, on the contrary, - 

 combines with it, is, that this acid evidently combines with 

 all the principles of alcohol without affording many diffe- 

 rent products, and that alcohol is a hydrogenous body as 

 well as the essential oil of turpentine. Yet whatever it may 

 be, nothing is more certain than that this combination has 

 the greatest resemblance to native camphor. 



Perhaps the camphor which is extracted from the essen- 

 tial oils of plants, particularly from jhat of lavender, is a 

 combination of essence and acid alone ; perhaps too the 

 camphor of commerce, or the camphor of the laurel, which 

 does not appear to contain any mineral acid, (for none can 



be 



