THE ENGLISH BOTANIST'S COMPANION: A CATALOGUE OF PLANTS FOR EVERY MONTH IN THE YEAR, WITH PRELIMINARY OBSERVATIONS. GARDENING, in common with the other arts, has, during the progress of the nineteenth century, become a subject of scientific investigation, and is no longer to be considered as a matter of mere routine practice. Knowledge, such as may be attained from the treatises of the old school,-or, to speak more correctly,—information, concerning the mechanical operations of digging and cropping the ground at specified periods, is doubtless of considerable utility; nevertheless, if practice be not founded upon the true principles of science and philosophy, there can be no certainty whatsoever of attaining successful results. Men may be industrious and watchful; they may call in aid all the mechanism of the art; still, however, owing to the exhaustion of the soil, or to the operation of natural causes but little understood, and probably not even suspected, their efforts may be baffled, and their hopes terminated by disappoint ment. This being the case, it becomes the indispensable duty of every one whose aim it is to understand any of the phenomena of vegetation, to inquire what are the nature, constitution, and offices of the agents by which such phenomena are produced, with the express view to acquire some knowledge of general principles, which may be reducible to practical utility. nized matter. The science of Gardening consists chiefly in a knowledge of those agents which nature employs in the production of vegetable orgaThese agents are numerous, and one or more of them, as has been already said, will come under consideration, and form the subject-matter of the leading section of each month. The first, and that which calls for the earliest notice as a primary agent, is the soil, its nature, and composition. But before we enter into an examination of the soil in which plants grow, and in order to obtain correct ideas on the subject of vegetable nutrition, it seems essential to devote some attention to the primary principles of plants themselves, and to inquire into the nature of those products of vegetable bodies, which have been obtained by the operations of analytic chemistry. We start upon true principles, when by any means we are enabled to determine the component parts of a vege table organized being; for, if these be clearly ascertained, it follows, as a necessary consequence that, by supplying that being with substances or matters which primarily contain, or are ultimately resolvable into its own constituent elements, we adopt the means best calculated to enable its organs to absorb nourishment suitable to its future growth and developement. Experiment has determined, that whatever be the parts of trees and plants that are submitted to the test of chemical analysis, whether it be the root, stem, branches, or leaves, the result is very nearly the same: they are all found to produce oxygen, hydrogen, and carbon, either separately, or united in various forms and proportions. These are terms which persons who are wholly uninitiated in the language of chemistry, may find, for a time, some difficulty to comprehend. Terms of science, which require elucidation, must, however, be occasionally employed; but it is hoped that, in the course of the work (although it is not to be considered a regular chemical treatise), so much elementary information will be conveyed, as shall not fail to remove many difficulties, to interpret and render perspicuous many heretofore unintelligible phrases, and gradually to lead the reader on, step by step, till he acquire a thorough relish for chemical pursuits, particularly when they are taken in connexion with vegetable physiology. Trees and plants yield a variety of compound products, possessing very different properties, and the greater part of them of essential utility to man. Among these products may be namedsugar, starch, gluten, gum, vegetable extract, bitter extractive, tannin, the colouring principle, acids, essential oils, the fat or fixed oils, resins, gum-resins, balsams, camphor, cork, &c.; also the sap, or ascending common juice; and the laborated sap, or proper juice,the origin of the foregoing secreted products. When these vegetable productions have been subjected to chemical analysis, they have been found to yield chiefly, carbon, oxygen, and hydrogen; and in some of them a portion of azot, or nitrogen, has been detected. Vegetables are found to contain two of the alkalies, namely, potass and soda, also two or more of their neutral compounds, as carbonate of potash, and muriate of soda (common salt). Nitrate of potash (salt-petre), is abundant in a few vegetables. The three earths, lime, or its carbonate, silica, and alumina, are traceable after burning; less frequently in the crude vegetable substance. The alkalies are abundant in the ashes of some plants; but it may be questioned, whether, in all cases, they exist originally in the plant, or are the results of combustion. However, De Saussure found |