1820. J Scientific Intelligence. 227 



Berchtesgaden. The simple solutions of these bodies in water 

 were not precipitated by nitromuriate of platinum ; but when 

 these solutions were concentrated till a considerable proportion 

 of the common salt was extracted, they then yielded a yellow 

 precipitate, when treated with this nitromuriate, indicating the 

 existence of potash. The same experiments succeeded with the 

 salt brine from Rosenheim, in the upper part of Bavaria. He 

 examined likewise the mother liquor, which drops from salt 

 extracted from salt springs, and obtained likewise a precipitate 

 with nitromuriate of potash. These experiments leave no doubt 

 of the existence of potash in common salt extracted from brine 

 springs, and show a striking analogy between these springs and 

 sea water. — (Gilbert's Annalen, Ixiv. 157.) 



III. Benzoic Acid. 



Hitherto benzoic acid has been found only in benzoin, storax, 

 balsam of Peru and Tolu, vanilla, cinnamon, and the urine of 

 several graminivorous animals, as cows, horses, camels, rhino- 

 ceros. Vogel has lately made a curious addition to the number 

 of plants which furnish it. He found it crystallized in the 

 Tonquin bean, between the skin and the kernel. It is well 

 known that this bean, as it is called, is the produce of a tree a 

 native of Guiana, which has received various names from bota- 

 nists. By Aublet, it is denominated Coumarouna odora; by 

 Gartner, Baryosma Tongo ; and by Wildenow, Diptert/x odoratu. 

 The only useful purpose, as far as I know, to which this bean is 

 put, is to give an agreeable odour to snufF. 



The crystals which Vogel found in these beaiTS melt at a mode- 

 rate heat into a transparent liquid, which, on cooling, suddenly 

 shoots out into stars, and then assumes the form of a crystallized 

 mass. If the temperature be increased, it sublimes, and is depo- 

 sited under the form of fine brilliant needles. The smell of these 

 needles is quite similar to that of the Tonka bean, the concen- 

 trated solution of these needles in alcohol reddens litmus paper, 

 and becomes milky when mixed with water. When saturated 

 with ammonia, these needles form a salt which throws down iron 

 with a brown colour. In short, they possess all the characters of 

 crystallized benzoic acid. 



M. Vogel has likewise detected benzoic acid in the flowers of 

 the trifulium melilotus officinalis. His method was to digest the 

 flowers in absolute alcohol raised to the boiling temperature. On 

 cooling, it let fall a fatty substance, and in two or three days 

 crystals of benzoic acid made their appearance in the liquid in 

 the state of long crystals. To separate these crystals from the 

 fatty matter, the whole was digested in boiling water, and the 

 liquid passed through the filter. The liquid containing the 

 benzoic acid passed through the filter, and when slightly evapo- 

 rated yielded the benzoic acid in crystals. M. Vogel thinks that 

 the quantity of benzoic acid in the blossoms of this plant is so 



p2 



