44S Chemical Analysis of the Green Shell of the IValnnt, 



black colour; there is also without doubt water produced; 

 so that altogcthtr the phsp-noincna of a real slow combustion 

 take place. The oxvgeuated muriatic acid appears to have 

 a difterent kind of action upon it, for instead ot blackening, 

 it causes it to lake a yellow colour; the same elieci is pro- 

 duced by the nitric acid. 



In order to proceed to the analysts of the matters con- 

 tained in the shell, I bruised a certain quantity of it in a 

 marble mortar; the expressed juice was passed through a 

 linen cloth and filtered; there remained upon the filter a 

 green fecula, which soon passed into a deep brown by the 

 contact of air; this matter, washed and dried, was put into 

 some alcohol, which extracted from it the green resin com- 

 mon to most vegetables: the residue, insoluble in alco- 

 hol, was still coloured, and soft to the touch ; a portion 

 of it was n)ixed with weak nitric acid, which converted it 

 into a thick viscid substance, soluble in water; alcohol pro- 

 duced from this solution a white flocculent precipitate. The 

 same coloured residue, mixed with water, containing a small 

 quantity of potass, produced an abundant quantity of a very 

 Jight substance, of a deep red coloi-.r, sin)ilar to the crassa- 

 menlum of the blood : lastly, another portion of the same 

 residue was treated by boiling water, and formed starch jelly ; 

 ■whence it results, that the substance contained in such 

 large quantity in the walnut shell is starch, contaminated 

 by the colouring matter. 



The juice of the walnut rind recently filtered is of an 

 amber colour, of an acrid and acid taste, mixed with some 

 bitterness ; the acrid principle appears to be readily destruc- 

 tible, for the recent juice when left to stand some days, in 

 changing its yellow colour for a blackish brown, where it 

 has been in contact with the air, loses also its acrid taste, 

 and becomes dccidcilly acid ; at the same time there arc 

 formed on its surface black pellicles, which are soon re- 

 newed after they have been removed': these pellicles, care- 

 ^■ullv collected and well washed, alford by drying, a black 

 brittle substance, of a shining vitreous fracture, and very 

 like asphaltum or Jews pitch, but burning without flame, 

 and therefore reseml^ling charcoal, 'i'his coaly matter is 

 soluble in potass, and is precipitated in (lakes by an acid. 

 It may be obtained more easily by evaporating, at a gentle 

 heal, the recent juice, and diluting the residue with water: 

 the supernatant liquor is of an agreeable acid taste ; whence 

 it results, that the acrid and bitter principle is entirely de- 

 stroyed, and appears to be converted into the black matter 

 Hearlv in the state of coal. No acetic vapours are disen- 

 gaged 



