66 Intelligence and Miscellaneous Articles. 



In a small tract printed ten years ago, I showed that the idea of an 

 absolute zero of cold expressible by a thermometer (Library of Useful 

 Knowledge, Heat, ch. viii.) involved some fallacy. Fill a cylindrical 

 tube with a heat-dilatable fluid, e. g. air, and continuing the divisions 

 to each end of the tube, we should find that as air expands ^l^th 

 in volume per degree from 32° Fahr. to 212° Fahr., the bottom 

 of the tube would have —480 + 32=— 448° Fahr. marked on it. 

 Fill such a tube with mercury, which expands g^o^th per degree 

 betwixt the same extremes, and the bottom of the tube will indicate 

 — [,'958° Fahr. Now could the substance ever contract to the 

 bottom of the tube, its density must become infinitely great, as it 

 then forms an infinitesimally thin stratum. May it therefore not be 

 concluded that every substance has its own minimum temperature 

 for maximum density, above or below which it expands just as water 

 on each side of 39° Fahr. ; the latter fluid having the lion's share of 

 this peculiarity, just as magnetism is ordinarily visible in iron above 

 all other metals, resembling in some sort the elective aflSnity so 

 common in chemical combinations ? 



London, Dec. 6, 1849. S. M. Drach. 



ACTION OF HYDROCHLORIC ACID ON THE HYDRATES OF OIL OF 

 TURPENTINE. BY M. II. DEVILLE. 



If one of the hydrates of oil of turpentine be treated with hydro- 

 chloric acid, water is separated and camphor formed, that is to say 

 a hydrochlorate of the oil combined with water. The product is not 

 similar to the solid camphor of turpentine, either in composition or 

 chemical properties, but it appears to be identical with the camphor 

 of oil of lemons. Its composition is as follows : — 



100 100-2 100-0 



Its melting-point is the same as that of the camphor of oil of 

 lemons, that is to say about 113°F. ; when this hydrochlorate is 

 heated, it is decomposed, and loses hydrochloric acid. Tieated with 

 potassium, it gives rise to a fluid colourless oil, the odour of which 

 may be mistaken for that of the oil of lemons, When the decom- 

 position is eflfected at the lowest possible temperature, the product 

 obtained has the sweet odour of lemon-peel; when, on the other hand, 

 the camphor is made to boil, so as to deprive it of acid as much as 

 possible, so that the decomposition by the potassium takes place at 

 a high temperature, the odour of the product resembles that of citren, 

 or the substance resulting from the action of lime on the oil of lemons* 



