\)\ih ^^d naphthaline, and on a new acid produced. 147 



The barytic salt in solution was now very carefully de- 

 composed, by successive additions of sulphuric acid, until all 

 the baryta was separated, no excess of sulphuric acid being 

 permitted. Being filtered, a pure aqueous solution of the 

 peculiar acid was obtained. It powerfully reddened litmus 

 paper, and had a bitter acid taste. Being evaporated to a 

 certain degree, a portion of it was subjected to the continued 

 action of heat ; when very concentrated it began to assume 

 a brown colour, and on cooling became thick, and ultimately 

 solid, and was very deliquescent. By renewed heat it melted, 

 then began to fume, charred, but did not flame ; and ulti- 

 mately gave sulphuric and sulphurous acid vapours, and left 

 charcoal. 



Another portion of the unchanged strong acid solution 

 was placed over sulphuric acid in an exhausted receiver. In 

 some hours it had by concentration become a soft white 

 solid, apparently dry ; and after a longer period was hard 

 and brittle. In this state it was deliquescent in the air, but 

 in close vessels underwent no change in several months. Its 

 taste was bitter, acid, and accompanied by an after metallic 

 flavour, like that of cupreous salts. When heated in a tube 

 at temperatures below 212°, it melted without any other 

 change, and on being allowed to cool, crystaUized from 

 centres, the whole ultimately becoming solid. When more 

 highly heated, water at first passed off, and the acid assumed 

 a slight red tint ; but no sulphurous acid was as yet pro- 

 duced, nor any charring occasioned ; and a portion being 

 dissolved and tested by muriate of baryta, gave but a very 

 minute trace of free sulphuric acid. In this state it was 

 probably anhydrous. Further heat caused a little naphthaline 



