of the State of New York. 



273 



occasions 



4. If the above remarks are correct, it follows as a consequence, 

 that in all cases where carbonate of soda is mixed with potash, the 

 relative proportions of these alkalies must be determined, before we 

 can fix the real value of the sample under examination. 



The only unexceptionable mode of separating potash fi'om soda, . 

 IS by means of nltro-murlate of platina; but this is an expensive 

 aticle, and its successful employment requires a nicety of manipula- 

 tion which can be expected only from the experienced chemist. An 

 approximation to a correct decision on this point may be attained by 

 adopting the steps prescribed in D and C, in the preceding formula. 

 By adding to a known quantity of the alkaline solution, an amount 

 of nitric acid sufficient for its neutralization, the sulphates and chlo- 

 ndes may be thrown down, first by the acetate of baryta, and after- 

 wards by the nitrate of silver. If the latter test 

 dant precipitate, we may infer that tlie solution contains an admix- 

 ture of common salt ; for although chloride of potassium is contained 

 in the purest samples of potash, it seldom constitutes more than two 

 or three per cent. 



It may also be mentioned that tartaric acid, when added to a por- 

 tion of the solution, will throw down the potash in the form of a dif- 

 ficultly soluble salt, (the bitartrate of potassa, or cream of tartar,) 

 but the soda will be retained In solution, and may be separated by 



subsequent evaporation. 



Difficult as are these methods of separating the salts of soda and 

 potash, and desirable as it would be to devise a more simple one, if 

 it is really an object to maintain a system of inspection worthy of 

 the name, heavy penalties should be affixed to the use of all adul- 

 terants and complete analyses of the various samples In market 

 should be made at short intervals by the inspector, or by some com- 

 petent person under his direction. 



Vol. XXIX.— No. 2. 



35 



