<P> Aluminium hydroxide, ferrous hydroxide, Gold Trihydroxide, </P> <P> The concept of base stems from an older alchemichal notion of "the matrix": </P> <P> The term "base" appears to have been first used in 1717 by the French chemist, Louis Lémery, as a synonym for the older Paracelsian term "matrix ." In keeping with 16th - century animism, Paracelsus had postulated that naturally occurring salts grew within the earth as a result of a universal acid or seminal principle having impregnated an earthy matrix or womb...Its modern meaning and general introduction into the chemical vocabulary, however, is usually attributed to the French chemist, Guillaume - François Rouelle...Rouelle explicitly defined a neutral salt as the product formed by the union of an acid with any substance, be it a water - soluble alkali, a volatile alkali, an absorbent earth, a metal, or an oil, capable of serving as "a base" for the salt "by giving it a concrete or solid form ." Most acids known in the 18th century were volatile liquids or "spirits" capable of distillation, whereas salts, by their very nature, were crystalline solids . Hence it was the substance that neutralized the acid which supposedly destroyed the volatility or spirit of the acid and which imparted the property of solidity (i.e., gave a concrete base) to the resulting salt . </P>

In chemestry a soluble base or a solution of a base