50

salt, common salt, salt of Sylvius, gypsum,phosphorated calx, and fixed alkalis.

Alkalis seem to be the product of the vege-table process, for either none or scarce any isfound in the soils, or in rain-water, while inthe vegetable they are, most probably, neutra-lised, partly by vegetable acids which are de-composed in the process of combustion, andpartly by the vitriolic and marine acids. West-rumb found tartar vitriolate and digestive saltsin the juices of trifolium.

Gypsum probably exists in greater quantityin plants than it appears to amount to aftercombustion and lixiviation; much of it mustbe decomposed during the combustion, and stillmore during lixiviation, by the alkalis existingin the solution. Thus the apparent quantity oftartar vitriolate is increased.

Phosphorated Calx is found in greatest quan-tity in wheat, where it contributes to the for-mation of the animal gluten. Hence in rainyyears the quantity of gluten in wheat has beenobserved to be smaller *. Hence the excel-

* 2d Witvver's Dissertations, 103.