ANALYSIS OF THE HUSKS OP WALNUTS.' 375 



the phenomena of a slow combustion. Oximuriatic acid Action of oxi- 



muriatic a 

 nitric acid. 



appears to have another kind of action on it; for, instead mu 



of blackening it, it causes it to assume a yellow colour. 

 Nitric acid comports itself in the same manner. 



To proceed to the examination of the matters contained Expressed juice 

 in the husk, I bruised a certain quantity in a marble mortar, ere * 

 expressed the juice, and filtered it. Some green feculae re- Residuum ex- 

 mained on the paper, which soon changed to a deep brown anuned - 

 by exposure to the air. This matter, washed and dried, 

 was macerated in alcohol, which extracted from it the green 

 resin common to most vegetables. The residuum insoluble 

 in alcohol was still coloured, and felt smooth. A portion 

 of it was diluted with weak nitric acid, which converted it 

 into a thick substance, viscous, and soluble in water. In 

 this solution alcohol occasioned a white flocculent precipi- 

 tate. The same coloured residuum, being diluted with 

 water to which a little potash was added, produced a bulky w 

 tremulous substance, of a deep red colour, and resembling 

 the coagulum of blood. Lastly another portion of the 

 same residuum was dissolved in boiling water, and formed 

 starch. Hence it follows, that this substance, contained 

 pretty abundantly in the husk, is starch contaminated by 

 the colouring matter. 



The juice of the husk recently filtered is of an amber Examination of 



colour, and of an acrid and sour taste mixed with bitter. the fiItered 



7 juice, 



ness. This acrid principle appears extremely destructible, 



for the recent juice, left to itself some days, while it loses 

 its yellow colour to assume a blackish brown where it has 

 been in contact with the air, loses also its acrimony, and 

 becomes decidedly acid: at the same time black pellicles 

 form on its surface, which are soon replaced by others if 

 removed. These pellicles, carefully collected and well 

 washed, yielded on drying a black, brittle substance, of a 

 shining, vitreous fracture, and pretty similar to asphaltum, 

 or Jew's pitch, but burning without any apparent flame, in 

 which it more resembled charcoal. This carbonaceous mat- 

 ter was dissolved in potash, and in this solution a flocCulent- 

 precipitate was produced by acids. It may be obtained 

 more readily by evaporating the juice of the husk with a 

 gentle heat, and diluting the residuum with water. The 



liquid 



