TURPENTINE. 419 



to each other. After this preparation it appears of a 

 golden colour. 



The quantity of turpentine retained for home 

 consumption in 1831 was 317,895 cwts. It is sub- 

 jected to a heavy duty of 4s. 4rf. per cwt., and if of 

 greater value than 12s. per cwt., a farther duty of Is. 

 per cwt. is exacted. Its present price is about 

 12s. 6d. per cwt., making the value of the turpentine 

 only Ss. 2d. per cwt. as imported. 



Turpentine is not used until it has undergone the 

 process of distillation. When distilled with water it 

 yields a considerable quantity of a subtile penetrating 

 essential oil, commonly termed spirit of turpentine. 

 The advantage of distilling with water was made 

 manifest by Neumann, who found that sixteen ounces 

 of Venice turpentine when mixed with water and 

 subjected to distillation produced four ounces three 

 drams of oil, and that the same quantity distilled 

 without water yielded with the heat of a water-bath 

 only two ounces. About six pounds of essential 

 oil is obtained from 25 Ibs. of good common turpen- 

 tine. After distillation with water a yellow sub- 

 stance remains in the still this is the common resin 

 of the shops. 



If this be now subjected to a greater heat a thick 

 balsam of a dark reddish colour, called balsam of 

 turpentine, is distilled over, and the residuum, which 

 assumes a blackish hue, is called black resin or 

 colophony. A patent has been recently granted for 

 the production and application of this balsam. 

 Common resin being procured it is distilled in the 

 manner above described, and the product is known 

 under the name of resin oil. This oil being decom- 

 posed by a similar process to that pursued with the 

 animal oils, is made like them to produce olefiant 

 gas for the purpose of illumination. 



Another patent has likewise been obtained for the 



