The alkalies, earths and acids

1166. The alkalies, earths, acids, and the combinations formed from them, are found in various quantities in different soils, and in addition to them are found various metallic substances, which are generally found in combination. There are several other elements found in plants, besides the four principal ones already mentioned, the most important of which are sulphur, chlorine, and phosphorus, but these are always found in combination with some other substance.