C 101 3 



turmeric ; or renders vegetable blues, green, it con- 

 tains alkali. 



To ascertain the relative quantities of pot-ashes 

 afforded by different plants, equal weights of them 

 should be burnt : the ashes washed in twice their 

 volume of water; the washings should be passed 

 through blotting paper, and evaporated to dryness : 

 the relative weights of the salt obtained, will indicate 

 very nearly the relative quantities of alkali they con- 

 tain. 



The value of marine plants in producing soda, 

 may be estimated in the same manner, with sufficient 

 correctness for all commercial purposes. 



Herbs, in general, furnish four or five times, and 

 shrubs two or three times as much pot-ashes as trees. 

 The leaves produce more than the branches, and the 

 branches more than the trunk. Vegetables burnt in 

 a green state produce more ashes than in a dry state. 



The following table* contains a statement of the 

 quantity of pot-ashes afforded by some common trees 

 and plants* 



10,OOO parts of Oak - - 15 



of Elm - - 39 



of Beech - - 12 



.__ of Vine 55 

 of Poplar 7 



of Thistle - 53 



of Fern - 62 



of Cow Thistle - 196 



* It is founded upon the experiments of Kirwan, Vauquelin and Pertuis. 



