134 Ckr. Phil. Pruckner on the [Aug. 



with which it is mixed. This object has been further 

 prosecuted more recently by Dr. Reichenbach, who has 

 separated several substances which make their appearance 

 during its purification. 



At the time when Priickner first engaged in the manufac- 

 ture of this acid, these substances were unknown, and conse- 

 quently his view of the theory of the method of obtaining 

 it pure, was quite different from that pointed out by Reichen- 

 bach. Now, however, when we possess an accurate know- 

 ledge of the products which come over in the purification 

 viz. Creosote Picamare, Paraffin, <fec., we may expect that 

 the process about to be described will be improved, so that 

 the last traces of foreign matter may be entirely removed. 

 The author considers that the present memoir, will not be 

 destitute of interest for a considerable period to the practi- 

 cal chemist, as the process described has been so frequently 

 repeated and examined, and that the publication will be of 

 advantage to proprietors and managers of chemical manu- 

 factories, who may, from the remarks offered, be enabled 

 to improve the process, by bringing the additional informa- 

 tion which may be acquired by the consideration of new 

 discoveries, to bear upon the subject. 



Many manufacturing chemists have long been endeavour- 

 ing to purify pyroligneous acid in different ways. The pro- 

 cess of Mollerat of Pellerey, who, by the formation of a 

 great chemical manufactory of this article, not only supplies 

 it for the use of France, but also exports it, is sufficiently 

 well known. It consists in forming the acetate of soda by 

 the double decomposition of acetate of lime and sulphate of 

 soda ; the acetate of soda being then roasted, the empyreu- 

 matic matter is driven off and the pure acetate of soda 

 remains. The objection to the use of this salt is, that at 

 an elevated temperature it melts, and that the surface of 

 it gradually becomes dry, while in the interior much water 

 still exists, and great difficulty is experienced in getting rid 

 of it, while to the acetate of lime the same objection is not 

 applicable. 



Preparation of the Acetate of Lime. — The crude pyrolig- 

 neous acid which is distilled from hard species of trees, as 

 the beech, oak, or alder, or from soft pines, receives a pre- 

 paratory purification in the following manner : — As much 



