The Farmer's Assistant Author:John Nicholson 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: FARMER'S ASSISTANT. AIR. Seeds which are buried so deep as to be secluded from their requisite portion of air will not vegetate; for this reasont weeds are co... more »nstantly springing up in new ploughed grounds; those seeds which before lay too deep for vegetation being turned up nigher the surface. Let seeds be sown in the glass receiver of an airpump, exhausted of air, and they will not vegetate; but admit the air and they will grow directly. The lodging, or falling, of some kinds of grain and of grass, is owing to standing too thick to admit a free circulation of ;.'ir, by means of which they can only preserve a healthy state. Plant one grain of wheat, for instance, in the richest soil, and the stalks when grown will not fall; but plant a great number of grains in the same soil, so closely together as to preclude a free circulation of air amongst the stalks, and they become unable to sustain their own weight. Air consists of different gases, as they are termed; the oxygene gas, or vital air, which is essential to the existence of all animals; the hydrogens gas, or inflammable air; the nitrogens gas, or common atmospheric air, deprived, of its oxygene, by having served the purposes of respiraiion or combustion, and which is also called azote; and the carbonic acid, formerly called fixed air, so often found fatal in the bottoms of wells and elsewhere. These are the principal ; but by the application of a sufficient degree of caloric (heat) all liquid substances can be changed into the gaseous state. The common atmosphere is principally composed of the oxygene and nitrogene gases, being about twenty-one parts of the former and seventy-nine of the latter. As ths oxygene or respirable air is essential to the existence of animals; so tHe hydrogene and the azote is absorbed...« less