224 
ON OIL OF TURPENTINE. 
chloric acid, which contains so much lead, is, of course not 
fit to be employed in chemical experiments. By distillation, 
however, the acid may be completely freed from that im- 
purity. No trace of lead is met with in the first receiver. 
Chemist, from Buck. Rep. 
ART. LXIV.— ON A MOLECULAR MODIFICATION OF OIL OF 
TURPENTINE, RENDERING IT CAPABLE OF MORE READILY 
DISSOLVING CAOUTCHOUC. 
By M. Bouchardat. 
Ten years ago, I was consulted by a manufacturer of 
water-proof cloth, to discover the best solvent for caout- 
chouc. At that time, the practice in England was to em- 
ploy coal-tar naptha, or an oil obtained by the distillation 
of caoutchouc over a naked fire. 
I commenced by carefully examining this pyrogenous 
oil. I separated from it several well-defined hydro-carbons, 
remarkable for their low boiling point, but I soon found 
that the price of this oil would long prevent its use in 
manufactures. The essential oil from coal has so disgust- 
ing and permanent a smell, that I resolved to seek for 
another solvent. 
From the first, I thought that turpentine, which, as is well 
known, dissolves caoutchouc, might be so modified by heat 
as to supply the solvent we required, and experience proved 
the truth of this supposition. By distilling oil of turpentine 
once or twice over a naked fire, we obtain a very satis- 
factory solvent. In making this distillation on brick, the 
essence being submitted to a higher temperature, it becomes 
