When a plant is burned it is reduced to a salty ash called alcaly 

 by apothecaries and philosophers . . . Every sort of plant without 

 exception contains some kind of salt. Have you not seen certain 

 labourers when sowing a field with wheat for the second year in 

 succession bum the unused wheat straw which had been taken 

 from the field? In the ashes will be found the salt that the straw 

 took out of the soil; if it is put back the soil is improved. Being 

 burnt on the ground it serves as manure because it returns to the 

 soil those substances that had been taken away. 



B. Palissy (1563) 



