47O Scientific Intelligence. [Dec. 



which constitute boletic acid. The properties of this acid are as 

 follows : — 



1 . When purified by solution in alcohol and crystallization it 

 is white, not altered by exposure to the air, and consists in irre- 

 gular four-sided prisms. 



2. Its taste is similar to that of tartar; it requires 180 times 

 its weight of water to dissolve it at the temperature of 68°. It 

 is soluble in 45 times its weight of alcohol. 



3. The aqueous solution reddens vegetable blues. Nitrate of 

 lead occasions a precipitate in it which is redisso ilvefl by agita- 

 tion. It precipitates the red oxide of iron completely from its 

 solutions in the form of rust-coloured flocks ; but it does not 

 throw down the black oxide of this metal. It precipitates nitrate 

 of silver in the state of a white powder, which is soluble in 

 nitric acid. Nitrate of mercury is precipitated in the same 

 state; but the solution dissolves with difficulty in nitric acid. 

 Neither lime nor barytes-water produce any effect upon the 

 aqueous solution of this acid. 



4. When heated it rises in white vapours, which irritate the 

 throat, and condense on surrounding bodies in the form of a 

 farinaceous powder. When distilled the greatest part of it sub- 

 limes unaltered, excepting that it afterwards crystallizes more 

 regularly. At the same time a little liquid appears, having a 

 strong smell of acetic acid. 



5. Boletate of ammonia is a salt which crystallizes in flat 

 four-sided prisms, and is soluble in 26 times its weight of water 

 at the temperature of 68°. Its taste is cooling, saline, and 

 somewhat sharp. When heated it melts, swells, and sublimes. 

 It precipitates red oxide of iron; but does not alter sulphates of 

 lime, alumina, or manganese. It slowly precipitates nitrate of 

 copper in blue silky needles. 



6. Boletate of potash is very soluble in water, and crystallizes 

 with difficulty. Acids precipitate the boletic acid from it. 



7. When boletic acid is heated with carbonate of lime it dis- 

 solves it with effervescence. The boletate of lime crystallizes 

 in flat four-sided prisms. This salt has little taste, and requires 

 at least 110 times its weight of water, at the temperature of 

 7'2'5°, to dissolve it. It is decomposed by oxalic and sulphuric 

 acids. 



8. Boletate of barytes is an acidulous salt in white plates, 

 little soluble in water or nitric acid. When thrown on a red-hot 

 iron it burns rapidly, with a red flame, and striking scintillations, 

 leaving for residue carbonate of barytes. 



9. When heated with iron filings and water, hydrogen gas is 

 emitted, and a yellow liquor is obtained with an inky taste. See 

 Ann. de Chim. vol. lxxx. p. 272. 



