CAMPHOR. 341 
If the crystallization of the natural camphor is watched by means 
of the microscope and polarized light, a most beautiful display of 
coloured crystals is seen, while with the artificial product nothing 
of the kind is witnessed *. 
Pinene hydrochloride or Pinyl chloride, C,)H,;Cl, was discovered 
in 1803 and described as artificial camphor +. This hydrochloride 
of oil of turpentine, or terpene monohydrochloride as it was sub- 
sequently called, is obtained by passing dry hydrochloric acid into 
French oil of turpentine { diluted with carbon disulphide § or 
benzene || ; according to Wallach these diluents are superfluous, it 
being only necessary to avoid the presence of any trace of water 
and to prevent the temperature rising. Pinyl chloride is a erystal- 
line mass which appears and smells like camphor; it is deposited 
from alcoholic solution in feathery crystals which possess the un- 
pleasant property of welding to a viscous mass, which adheres 
firmly to all objects with which it comes in contact. It melts at 
125° and boils at 210°. 
Camphene may be readily obtained by heating equal parts cf 
pinyl chloride and anhydrous sodium acetate to 200° for three or 
four hours with twice the weight of glacial acetic acid or by 
simply heating a mixture of pinyl bromide and glacial acetic acid 
for some time in a flask connected with an inverted condenser 4. 
It forms a crystalline mass resembling paraffin, of a smell which is 
considered to resemble a mixture of turpentine and camphor. 
Camphoric acid, C\)H,,O,. According to Wreden **, 150 grams 
of camphor and 2 litres of nitric acid (sp. gr. 1:27) are brought 
into flasks of 4 litres capacity, a conducting-tube for the nitrous 
fumes being fastened in the neck by means of plaster-of- Paris. 
The mixture is heated on a briskly-boiling water-bath until the 
vapours are only slightly coloured, the operation lasting about 
50 hours. The product is then converted into the sodium salt and 
this once re-crystallized. About 725 to 800 grams of pure cam- 
phoric acid are obtained from 1500 grams of camphor. It is 
* Silliman’s Journal, May 1851. 
+ Trommsdorff’s ‘Journal of Pharmacy,’ xi. 2. p. 13 
{ Pogg. Ann. xxii. p. 89. 
§ Ann. Chim. Phys. [3] xl. p. 5. 
|| Ber. Deutsch. chem. Ges. xii. p. 1131. 
4, Bull. Soc. Chim. cexxxix. p. 6. 
** Ann, Chem. Pharm. clxiii. p. 323. 
ts 
