Absorption. In agriculture, the power possessed by soils of absorbing moisture from the atmosphere. The more a soil is divided by labour and vegetation, the greater is its absorbent power, and, consequently, its fertility. Indeed, the latter chiefly depends on its capacity for imbibing moisture, and may be illustrated by reference to recent and disintegrated lava. (Leslie.) The finely divided state, most penetrable by the delicate fibres of plants, appears to derive its superior power of acting on atmospheric vapour from the augmentation of its surface and the multiplication of its points of contact. (Ure.) This method of increasing the fertility of a soil is well known to scientific farmers, and seldom neglected by them. (Loudon.) That soil must be regarded as the most fertile which possesses this power in the greatest degree. Garden-mould has the highest absorbent power of any mineral substance. (Leslie.)
Process of ascertaining the ABSORBENT POWER OF SOILS, and other substances. Thoroughly dry the article by the suitable application of a heat not exceeding 212° Fahr., continued for several hours, and transfer it, while still warm, into a clean dry phial furnished with a perfectly tight ground-glass stopper. When cold, quickly and cautiously introduce it, along with a delicate hygrometer, into a large wide-mouthed glass bottle, the atmosphere of which has been previously rendered as damp as possible, by suspending a piece of moistened rag or filtering paper in it. It must now be kept closed for some hours, when the hygrometer will indicate the degree of dryness of the enclosed air, and, consequently, the absorbent power of the substance examined.
Obs. Experiments of this nature are only relatively correct, and must be performed under exactly similar circumstances, to furnish reliable comparative results. The whole process, in each case, must be as similar as careful manipulation can possibly make them. With this reserve, they will be found invaluable to the agriculturist.
Absorption. In chemistry the passage of gases and vapours into liquid and solid substances. Thus, water absorbs the oxygen of the air, lime absorbs water, charcoal absorbs ammoniacal and other gases.
Absorption. In medicine and toxicology, see Medicines and Poisons.
Absorption. In perfumery, see Enfleurage.
Absorption. In physics, see Heat, Light, Refrigeration, &c.
Absorption. In physiology (animal and vegetable), the function of sucking, or taking up, of appropriate substances, by the ‘absorbent vessels.’ It is one of the chief vital functions, the primary object of which is to convey to the circulatory organs the proper supply of the materials necessary for the support and growth of the body; and subsequently, to remove and convey to these organs its effete and useless portions, in order to their ultimate elimination from the system.
Absorption. In surgery, the natural process by which tumours and their contents, morbid growths, and, sometimes, even healthy glands, &c., are gradually taken up and disappear, by the action of the ‘absorbents.’
Absorption (of Surfaces, Moulds, &c). See Absorbent Surfaces.