Intelligence and MIscellaneons Articles. 317 



phurous acid is given out ; nitric acid converts it into phosphoric 

 acid. 



When mixed w^ith chlorate of potash it gives a fulminating pow- 

 der, which detonates, sometimes, during the mixture, and without 

 giving it any pressure ; a slight pressure always occasions it to ex- 

 l)lode. The hydrate of phosphorus, which has been mentioned, de- 

 composes in vacuo, or by exposure to the air at common temperatures. 

 The quantity of water which it contains was determined by indirect 

 processes to be 20*5 per cent., so that it is composed of one eq. of 

 oxide 72 + 2 eqs., water 18 = 90, very nearly. — Annates de Chimie 

 et de PJiysique, Juillet 1837. 



BORATES OF POTASH. BY M. LAURENT. 



The borates of potash were prepared by decomposing a hot solu- 

 tion of carbonate of potash with excess of boracic acid. A part of 

 the salt was made to crystallize, and to the remaining solution a 

 little caustic potash was added, and crystallization was effected after 

 each addition of the alkali. The crystals which were formed were 

 kept separate and examined. 



Sexbonite of Potasli is deposited from a solution which is either 

 acid or neutral to litmus paper. The crystals belong to the right 

 prismatic system (right rhombic prisms) and are generally modified 

 on the edges or angles, and are occasionally tabular and thin. The 

 forms are not readily perceived on account of the crystals being 

 hemitrope. 



This salt is unalterable in the air ; very brilliant ; it is but slightly 

 soluble in cold water, but readily dissolved by boiling water; it is 

 neutral to litmus paper, or rather it blues it slightly. 



This salt was analyzed by passing gaseous hydrofluoric acid on 

 the pulverized borate, moistened and placed in a platina crucible ; 

 the fluoride of potassium was converted into neutral sulphate by 

 sulphuric acid, calcination, and the addition of carbonate of ammonia. 

 The results of the analysis were — 



By Experiment. Calculated. 



Boracic Acid - - - 60-8 60-5 



Potash 14-0 1.3-6 



Water ----- 25-2 25-2 



100-0 



The calculation was made according to the following formula : — 

 6B^03 + K O 4 10H"-O. 



Taking Berzelius's recent atomic weight of boracic acid as B'^ O^, 

 it will be seen that this salt, which is rather alkaline than acid, con- 

 tains, nevertheless, six atoms of acid. 



Triborate of Soda. On gradually adding potash to the preceding 

 salt, the liquor becomes alkaline, and by evaporation it deposits at 

 first a confusedly crystalline crust, which appeared, however, to be 

 sexborate, and the mother waters eventually yielded biborate. Some- 

 times, and especially at the surface of the solution, there are 

 formed very distinct crystals presenting the form of rectangular 



