Note 2875 — BOOK XVII. THE NATURAL HISTORY OF THE CULTIVATED TREES.
John Bostock translation
A natural mixture of argilla and calcareous stones, or subcarbonate of chalk. Fée remarks, that the ancients were not acquainted with the proper method of applying it. Marl only exercises its fertilizing influence after being reduced to dust by the action of the atmosphere, by absorbing the oxygen of the air, and giving to vegetation the carbonic acid that is necessary for their nourishment.