464 Scientific Intelligence. [June, 



of potashin which the acid was in excess, might be rendered alkaline br 

 the addition of boracic acid. He dissolved carbonate of potash in fluoric 

 acid, and used so much of the acid that the solution reddened litmus 

 paper very sensibly, and the free acid did not disappear even when the 

 solution hod been kept boiling for a quarter of an hour. When boracic 

 acid that had been melted, dissolved in water and crystallized again, 

 was added, it easily dissolved. Now a solution of litmus showed much 

 less acid thanbefore. After the addition of a new quantity of boracic 

 acid, no trace of free acid could be found by litmus ; and after a fresh 

 addition of boracic acid, the solution exhibited the appearances of 

 alkali ; for a solution of litmus reddened by the above-mentioned fluate 

 of potash became blue when mixed with a few drops of this solution. 

 When the quantity of boracic acid was further increased, the solution 

 became again acid. Not a trace of acid was lost during this experi- 

 ment under the form of vapour or gas ; for moistened litmus paper 

 placed above the liquid had not in the least changed its colour. Pure 

 fluoric acid and pure boracic acid, when mixed in different proportions, 

 never showed any similar appearance, nor was it expected. 



A solution of litmus reddened by a solution of boracic acid wai 

 mixed with another solution of litmus reddened by acidulous fluate of 

 potash, and a blue colour instantly appeared. The same effect took 

 place when ammonia or soda was substituted for potash. Litmus paper, 

 when reddened by the bifluate of potash, became red when put into 

 a solution of boracic acid, either in alcohol or in water. Litmus paper 

 reddened by boracic acid was turned blue by the acidulous fluate of 

 potash, and the blue colour was again changed to red by another 

 acid. 



Syrup of violets reddened by the fluate of potash became, on addi- 

 tion of bpracic acid, first blue, afterwards green. Turmeric paper and 

 logwood paper suffered corresponding changes of colour, so that all 

 tests proved the disengagement of the alkali by the addition of boracic 

 acid. 



This very curious observation of Dr. Zeise seems clearly to prove 

 that the fluoboric acid neutralizes less alkali than any one of its consti- 

 tuent parts would saturate alone. Analogous, but not so remarkable, 

 is the hyposulphuric acid which neutralizes only as much of a base, as 

 each of its component acids neutralizes separately. 



[Many of the facts here stated may be explained by Mr. Faraday's 

 discovery, that boracic acid reddens turmeric paper. — Edit."] 



(See Institution Journal, vol. 6, p. 152; and vol. 11, p. 4?03.) 



IV. Analysis of Lepidolite, By Dr. C. G. Gmelin and Winz. 



Gmelin some time since observed, that the lepidolite from Utoen, 

 when treated with carbonate of barytes, had acted upon the platinum 

 of the crucible, he therefore suspected it to contain lithia, and found 

 it in the following way : He boiled finely powdered lepidolite with sul- 

 phuric acid to dryness, and dissolved the residuum in water. By slow 

 evaporation, fine crystals of alum were obtained. The remaining solu- 

 tion was saturated with carbonate of ammonia, and after the removal 

 of the precipitate, evaporated, and the salt heated to redness. The 

 sulphate was dissolved, and after having deposited some traces of 

 manganese, it was mixed with hydrosulphuret of ammonia, the excess 

 of which was removed by heating the liquid. The sulphate was then. 



