Chemical Science. 351 



sensibly acid taste* and applied to litmus paper, distinctly reddens 

 it, though containing no foreign acid. 



It is scarcely soluble in cold water, but a solution may be 

 obtained, sensible to re-agents. Boiling water has a stronger 

 action ; the filtered liquor is colourless, deposits nothing on 

 cooling, and barely reddens litmus. Alcohol coagulates it into a 

 transparent jelly, colourless as ice ; so also do all metallic so- 

 lutions, lime water, baryta-water, acids, muriate and sulphate of 

 soda, nitrate of potash, &c. This acid appears to be held so 

 feebly in aqueous solution, that the solution of a little sugar is 

 sufficient to make the greatest part of the liquor coagulate. 



Dried in a capsule, it appears in transparent films having 

 no adhesion to the vessel. When dry, it scarcely swells in cold 

 water ; dissolves in small quantities in boiling water, and offers 

 the phenomena just described. 



The acid precipitated from its potash combination by muriatic 

 acid, when distilled, did not swell up, and gave a product con- 

 taining much empyrumatic oil, but no ammonia, nor muriatic acid ; 

 much charcoal remained. 



Diffused through water, and aided by warmth, it disengages 

 carbonic acid from its alkaline combinations. 



It forms a very soluble salt with potash, which may be obtained 

 in the state of transparent jelly, by adding weak alcohol, which 

 removes the excess of alkali, and colouring matter, if there be 

 any. This jelly, washed on a cloth with alcoholized water, 

 pressed, and dried, is a neutral combination, which swells and 

 dissolves in water, and leaves, upon evaporation of the liquid, a 

 transparent mass, full of cracks, and resembling gum-arabic in 

 appearance; it has so little disposition to adhere, that the slight- 

 est friction removes it entirely from the capsule. The taste of 

 this salt is insipid ; put upon a plate of red-hot iron, it swells 

 excessively, leaving a deep-brown residue, soluble in water, and 

 having the character of ulmin, united to potash. Exposed to the 

 flame of a taper, it burns, producing delicate filaments, which 

 project out from the mass like vermicelli. These filaments 

 fuse into globules of sub-carbonate of potash. 



This salt, in aqueous solution, is gelatinized by alcohol, sugar, 

 muriate of soda, acetate of potash, and other neutral salts. All 

 earthy and metallic salts decompose it by double affinity. The 

 acids unite to the alkali, and separate the acid as a jelly. One 

 hundred parts of the neutral combination burnt in a platina cruci- 

 ble, left a quantity of sub-carbonate of potash, which, heated 

 to redness with sulphuric acid, gave 28 parts of sulphate of potash, 

 from which it would appear that the salt was formed of 

 Acid ... 85 



Potash . . . 15 

 100 



