CHAPTER III.

OF BOTANY.

SECTION I.

863. THE Second and intermediate science of Physics, termed BOTANY, comprehends whatever in science belongs to Vegetation and the organization of matter, and might, therefore, be appropriately called Phytology.

864. The inorganic substances of Chemistry are the ground and support of the organic productions of Botany, or of all Vegetal nature; and Vegetals, in their turn, afford the matter, and become the sustenance, of all animal and sensitive nature for vegetals supply elastic oxygen to the air, and hydrogenous and carbonaceous solid edibles to animals, from which, in return, they receive carbonic gas, azote, and hydrogenous manures, &c.

865. That which the Polypi are in animal nature, the Fungi are in vegetal nature: the one

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is the intermediate of the animal and vegetal kingdoms, the other connects the vegetal with the mineral kingdom, while their extremes, the mineral and animal, are united by the Zoophytæ ; the links by which the genera of Physics are connected.

866. As Chemic matter requires to be elaborated by vegetation before it can become the food and sustenance of animals, Vegetation is the chief mean by which sensitive being is united with the material.

867. Botany, therefore, takes in Physics the relation of medium, and participates of its two extremes. Hence, not only are there in this respect three orders or genera of plants, but Botany is also allied to Chemistry in respect to the soil and matter of vegetals; and to Medicine, or animal science, in respect to their organization and functions.

868. We may, therefore, divide Botany into three parts, or subordinate sciences: the first, in respect to the Chemistry of Botany, or the elementary principles of vegetals; the second, in respect to the relations of vegetals, their genera and species, &c., or Particular Botany; and the third, in respect to the organs, offices, and purposes, of vegetal, or Organic or Medical Botany, which together comprehend the matter, form, and functions, of Vegetals.

SECTION II.

869. To the first, or CHEMICAL BOTANY, belongs Agriculture, which comprehends the matrix, or soil of plants, their pabulum, or food or manure, &c., and the products or fruits of Vegetals.

870. Accordingly, Soils, or the matrix of plants, consist of the various substances of Chemistry, but principally of the Earths, in which the agriculturist has primarily the Calcareous, or Chalky soil; the Argillaceous, or Clayey soil; and the Siliceous, or Sandy soil.

871. Soils are, secondarily, the Marly soil, composed of Clay and Chalk; the Loamy soil, composed of Sand and Clay; and, more rarely, a soil composed of Sand and Chalk: but soils in general consist of mixtures of the above three primary kinds of Earths, and the best soils are constituted of these in certain harmonic proportions.

872. In this respect, also, nature has every where harmonized the superstrata with the substrata of land; so that there is no soil, however barren, that has not beneath it the materials and principles by which it may be fertilized: thus, beneath Sand, is found clay, loam, or marl; beneath Clay, sand and chalk, or limestone; and, beneath Chalk, is found silex or sand, and clay, &c. and these by mixture fertilize each other.

873. It is not, however, to be understood that soils exist commonly in the absolute simplicity and order above mentioned, but only that they may be thus relatively distinguished, since they are compounded with all the substances of nature, and in boundless variety adapted to the support of the various vegetal tribes; which are also, doubtlessly, qualified by a corresponding analogy of genera and species to those of the soils whereon they are destined to flourish.

874. The Pabulum, or food of plants, involves the Solids, Liquids, and Elastics of Chemistry: of the first of which are hydrogenous, nitrogenous, and carbonaceous Manures, mineral, vegetal, and animal; of the second is Water, which is medial and principal in vegetations; and, of the third, are oxygenous Airs, Light, and Heat, by which vegetals are actuated in fine, the Agent and Patient, the Oxygenous and Hydrogenous Elements of Chemistry, are those which form, increase, and nourish vegetal substances.

875. And so admirably are the chemical relations and natural harmonies of material things adapted to each other, that the Manures, by which vegetal productions are increased, are natural to the soils by which they are produced, and the animals by which they are consumed return gratefully to the soil that feeds them manures adapted to produce those plants which are again best suited to their own sustenance: thus, the

manure of sheep and rabbits fertilizes the soil for fine herbage; that of kine, for rank herbage; while that of man is adapted to the vine, corn, and the fruit of trees; and it may be regarded as a general law, that every animal affords those principles of fertility which encourage with the best economy those productions of the soil which are best adapted to its own nature and improvement; whence the horticulturist may draw from analogy means for invigorating and carrying to perfection, according to their uses, the various races and kinds of plants.

876. And, finally, of the Products of plants, are the various drugs, aliments, and materials, which sustain the life, growth and vigour, restore the health, or contribute to the convenience, enjoyment, and well-being of the animal frame and nature. So much concerning the divisions of chemical Botany, and the beginning, means, and end of Agriculture in its widest acceptation.

SECTION III.

877. Secondly, of the Relations of Plants, or Particular Botany, to which the term Botany has in its ordinary sense been almost exclusively confined; yet this is more properly Phytology, or the Natural History, than the science of vegetal nature, although it is subject to the same analogy. Such