The principles of agriculture and vegetation / By Francis Home.

  • Francis Home
Date:
1759
Catalogue details

Licence: Public Domain Mark

Credit: The principles of agriculture and vegetation / By Francis Home. Source: Wellcome Collection.

    70/228 (page 56)
    The fame quantity of ftone marl, treats ed the fame way, afforded juft the fame proportion of clay and calcarious earth. Marl, then, is a body compofed of lime and clay in different proportions, accord¬ ing to the different kinds of marl, and ge¬ nerally about one fourth of lime and three fourths of clay, From this experiment we may ealily account why marl falls in water, as lime ftrongly attracts water ; and why it lofes this property when burnt, as clay becomes more tenacious by fire ; why it cannot be converted to brick, as the lime hinders that clofe adhefion of the particles of clay which is neceffary to conftitute brick 5 why it will not vitrify, as lime is an enemy to all vitrification 5 and why it ftiews a fmall portion of oleaginous matter, as clay con¬ tains fome oil. By mixing quick or rather effete lime with clay, or a clay foil, we imitate^