Professor GmeliiVs Analysis irf Helvine. 273 



ash ; from the ammoniacal liquid the eartli separates by 

 boiling as a light Jiocculent powder, which, when washed upon a 

 filtre with boiling water, is dissolved by acids with efferves- 

 cence, and forms no alum with sulphuric acid and potash. 

 This earth is likewise dissolved by a solution of subcarbonate of 

 potash, when it is precipitated from its solutions by an excess 

 of this salt, and the liquor boiled. When this earth is precipi- 

 tated from its solutions by caustic ammonia, and this alkali is 

 added in a very great excess, almost no perceptible quantity of 

 it is dissolved, which falls down again, when the excess of 

 ammonia is expelled by heat. With an excess of muriatic acid 

 a mass not distinctly crystallized is formed during evapora- 

 tion, which deliquesces in the air, and is decomposed by heat 

 in muriatic acid and earth that is left. This muriate has a very 

 sweet, and at the same time an astringent, and not metallic taste. 

 Combined with sulphuric acid it crystallizes by a slow evapor- 

 ation, when the acid is only added in the quantity required 

 for its solution. The sulphate has an acrid taste ; it is de- 

 composed by a moderate ignition ; only a small portion of the 

 residue is dissolved in water ; by far the greatest part is left 

 undissolved, in the form of a mucilaginous substance. 



In acetic acid this earth is dissolved, the solution does not 

 crystallize by evaporation; by a slow evaporation a gummy-like 

 transparent mass is formed, which does not attract humidity 

 of the air, becomes full of cracks, and dissolves anew in water ; 

 by a quicker evaporation the residue becomes in part milky. 

 Sulphuretted hydrogen forms no precipitate in the solutions 

 of this, earth. Caustic potash dissolves it, as it appears al- 

 ready from the analysis. 



This earth is therefore glycine, mixed with a very small 

 quantity of alumine, and helvine is composed of — 



