.j^ Experiments and Ohferuations 



than that which exilts l^etween this and the vitriolic acid ; the 

 firft will therefore be diflodged, and the fuperabundant acid of 

 the foil be abforbed by the Calcarious earth. 



It is evident, then, that Gypfious earths contain an acid, 

 capable, when united with an alkali, of forming a neutral faltj^ 

 in which water is a principal ingredient. This earth alfo con- 

 tains phlogifton, or a principle of inflammability ; as I infer, 

 ift, from limeftones being ufed as a flux for fubftances which 

 cannot otherwife be reduced by fire, as pure clay, &c. &:c, 

 ad, from its having once formed part of an organized animal^ 

 3d, from fome experiments of Doftor Prieftly, in which he 

 exprefsly declares that he got a confiderable quantity of 

 inflammable air from chalk, by the application of heat ; 4th, 

 from the following experiment, which, being new to me, 

 furprized me much : I put a few fpoonfuls of chalk into a 

 glafs bottle, to which I poured flirong white wine vinegar, and 

 corking the bottle, (after the firft ebulition was over) at the 

 end of a fortnight, I found the vinegar, from a tranfparent, 

 converted into a dirty black liquor. This change of colour I 

 can only account for by fuppofing that the phlogifton contained 

 in the chalk was fet loofe by its decompofition, and imbibed 

 by the vinegar. 



Thus, then, we find in a Calcarious earth, moft of the 

 elements that go to the compofition of vegetables, to wit, earth, 

 air, fire, water, — and an acid, capable, by its combination 



