1818.] M. Vogel on Borax and Tartar. 113 



burned with much flame and smoke. Adds acted on it as on 

 naphtha, giving it the appearance of petroleum. The other fluid 

 was colourless, uninflammable, had a strong ammomacal odour, 

 and effervesced with acids ; in short, seemed to be some of the 

 ammoniacal fluid, produced during the distillation of the coal, 

 from which it is very difficult to free the tar entirely. 



I redistilled the first mentioned fluid, and obtained a light 

 straw coloured oil, very inflammable, having a strong and pecu- 

 liar smell, and extremely volatile. A little of it rubbed on the 

 hand evaporated almost instantly, leaving the part quite dry. 

 Its specific gravity I found to be about "770; thus showing all 

 the properties of naphtha in a state of purity. 



I next proceeded to try the effects of this naphtha on caout- 

 chouc. For this purpose I selected that kind of it which is met 

 with in the shops, of a white colour, and in form of a cake. 

 Some slips of this being put into a bottle and covered with the 

 naphtha, soon began to swell, and in a few hours were in such a 

 state that upon being stirred they cohered together, and formed 

 a homogeneous mass. 



I found that this mass might be brought to any degree of 

 fluidity by the addition of the naphtha. When a little of this 

 solution was exposed to the air, the naphtha speedily evaporated, 

 leaving the caoutchouc, which in a short time resumed its 

 original elasticity. 



Therefore, I think that I may with confidence recommend 

 this fluid as being free from all the disadvantages of the hitherto 

 known solvents of that substance ; and I hope that it may be the 

 means of extending its use to the many purposes for which it is 

 so peculiarly well adapted. 



Article VI. 



Researches upon the Action of Borax, the Boracic Acid, and the 

 neutral Borates upon the acidulous Tartrates of Potash and 

 Soda. By M. Vogel* 



The author divides his memoir into two sections ; in the first, 

 he examines the action of borax upon cream of tartar ; and in 

 the second, he describes the phenomena which take place when 

 we treat the cream of tartar and the acidulous tartrate of soda 

 with boracic acid and the neutral borates. The best proportions 

 for combining the cream of tartar and borax are three parts of 

 the first to one of the last ; if these bodies be boiled for a few 

 minutes with a sufficient quantity of water, a portion of tartrate 



» Abstracted from a memoir read to the Royal Academy of Munich,— Journ. 

 Pharm. iii. 1. (Jan. 1817.) 



Vol. XII. N° II. H 



