Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: PART I. OF THE CHEMICAL PROCESSES IN THE NUTRITION OF VEGETABLES. CHAPTER I. OF THE CONSTITUENT ELEMENTS OF PLANTS. The ultimate constituents of plants are those which form organic matter in general, namely, Carbon, Hydrogen, Nitrogen, and Oxygen. These elements are always present in plants, and produce by their union the various proximate principles of which they consist. It is, therefore, necessary, to be acquainted with their individual characters, for it is only by a correct appreciation of these that we are enabled to explain the functions which they perform in the vegetable organization. Carbon is an elementary substance, endowed with a considerable range of affinity. With oxygen it unites in two proportions, forming the gaseous compounds known under the names of carbonic acid and carbonic oxide. The former of these is emitted in immense quantities from many volcanoes and mineral springs, and is a product of the combustion and decay of organic matter. It is subject to be decomposed by various agencies, and its elements then arrange themselves into new combinations. Carbon is familiarly known as charcoal, but in this state it is mixed with several earthy bodies; in a state of absolute purity it constitutes the diamond. Wood charcoal contains about l-50th of its weight of alkaline and earthy salts, which constitute the ashes when it is burned. Hydrogen (Inflammable Air) is a very important constituent of vegetable matter. It possesses a special affinity for oxygen, with which it unites and forms water. The whole of the phenomena of decay depend upon the exercise of this affinity, and many of the processes engaged in the nutrition of plants originate in the attempt to gratify it. Hydrogen, when in the state of a gas, is very combustible, and the lightest b...