CHALK, in natural history, the English name of the white, dry marble, with a dusty surface, found in hard masses, and called by authors creta, and terra creta.
Chalk thrown into water, raises a great number of bubbles, with a hissing noise, and slowly diffuses itself into an impalpable powder. It ferments more strongly with acids than any other earth, and burns to lime.
As a medicine, chalk deserves, perhaps, the highest place among the alkaline absorbents; nor is it less useful in many of the ordinary affairs of life. Its use in cleaning various utensils is well known; and it is in no small repute as a manure, especially for cold sour lands; in which intention the soft unctuous chalk is most proper, as the dry, hard, and strong chalk is for lime. It is a great improver of lands, and will even change the very nature of them. However, it is most advisable to mix one load of chalk, with two or three
of dung, mud, or fresh mould, whereby it will become a lasting advantage to the ground: The common allowance is fourteen loads of chalk to every acre.