n 



Anatomy of the Vine. 



the cork of the bottle by a bit of wood), on a piece of white paper, 

 and, about 1 in. from it, deposit as much of the sulphate 

 of iron ; afterwards double the paper between them together, 

 and the instant the two solutions unite, a beautiful blue 

 precipitate or sediment will be seen, which colour is com- 

 monly called the Prussian blue. This precipitate arises 

 from the union of the prussic acid in the prussiate of pot- 

 ash, with the iron in the sulphate of iron. Again, place 

 on a bit of paper the decoction of oak galls or tea, and 

 add the sulphate of iron as before ; as soon as they unite, 

 a fine black precipitate will be discovered, similar to com- 

 mon writing-ink; this black colour arises from the gallic 

 acid in the decoction, precipitating the iron in the sulphate of 



a b n c n d 



On looking attentively on the separated ends of the collet, 

 the eye may easily perceive that the circle round the pith is 



