1826.] Sitlpho-Naphthalic Acid. 189 



2. Salts formed by the peculiar acid with bases. These 

 compounds may be formed, either by acting on the bases or 

 their carbonates by the pure acid, obtained as already de- 

 scribed ; or the impure acid in solution may be used, the salts 

 resulting being afterwards freed from sulphates, by solution in 

 alcohol. It is however proper to mention that another acid, 

 composed of the same elements, is at the same time formed 

 with the acid in question, in small, but variable proportions. 

 The impure acid used, therefore, should be examined as to 

 the presence of this body, in the way to be directed when 

 speaking of the barytic salts ; and such specimens as contain 

 very little or none of it should be selected. 



Potash forms with the acid a neutral salt, soluble in water 

 and alcohol, forming colourless solutions. These yield either 

 transparent or white pearly crystals, which are soft, slightly 

 fragile, feel slippery between the fingers, do not alter by 

 exposure to air, and are bitter and saline to the taste. They 

 are not very soluble in water ; but they undergo no change by 

 repeated solutions and crystallizations, or by long-continued 

 ebullition. The solutions frequently yield the salt in acicular 

 tufts, and they often vegetate, as it were, by spontaneous eva- 

 poration, the salt creeping over the sides of the vessel, and 

 running to a great distance in very beautiful forms. The 

 solid salt heated in a tube gave off a little water, then some 

 naphthaline ; after that a little carbonic and sulphurous acid 

 gases arose, and a black ash remained, containing carbon, 

 sulphate of potash, and sulphuret of potassium. When the 

 salt was heated on platinum foil in the air, it burnt with a 

 dense flame, leaving a slightly alkaline sulphate of potash. 



Soda yields a salt in most properties resembling that of 

 potash, crystalline, white, pearly, and unaltered in the air. I 

 thought that, in it, the metallic taste which frequently occurred 

 with this acid and its compounds was very decided. The 

 action of heat was the same as before. 



Ammonia formed a neutral salt imperfectly crystalline, not 

 deliquescent, but drying in the atmosphere. Its taste was 

 saline and cooling. It was readily soluble in water and alcohol. 

 When heated on platinum foil it fused, blackened, burnt with 

 flame, and left a carbonaceous acid sulphate of ammonia, which 

 by further heat was entirely dissipated. Its general habits 



