DRY ROT

dry rot, a fungoid disease in timber which occasions the destruction of its fibres, and reduces it eventually to a mass of dry dust. it is produced most readily in a warm, moist, stagnant atmosphere, while common or wet rot is the result of the exposure of wood to repeated changes of climatic conditions. the most formidable of the dry rot fungi is the species _merulius lacrymans_, which is particularly destructive of coniferous wood; other species are _polyporus hybridus_, which thrives in oak-built ships, and _p. destructor_ and _thelephora puteana_, found in a variety of wooden structures. the felling of trees when void of fresh sap, as a means of obviating the rotting of timber, is a practice of very ancient origin. vitruvius directs (ii. cap. 9) that, to secure good timber, trees should be cut to the pith, so as to allow of the escape of their sap, which by dying in the wood would injure its quality; also that felling should take place only from early autumn until the end of winter. the supposed superior quality of wood cut in winter, and the early practice in england of felling oak timber at that season, may be inferred from a statute of james i., which enacted "that no person or persons shall fell, or cause to be felled, any oaken trees meet to be barked, when bark is worth 2s. a cart-load (timber for the needful building and reparation of houses, ships or mills only excepted), but between the first day of april and last day of june, not even for the king's use, out of barking time, except for building or repairing his majesty's houses or ships." in giving testimony before a committee of the house of commons in march 1771, mr barnard of deptford expressed it as his opinion that to secure durable timber for shipbuilding, trees should be barked in spring and not felled till the succeeding winter. in france, so long ago as 1669, a royal decree limited the felling of timber from the 1st of october to the 15th of april; and, in an order issued to the commissioners of forests, napoleon i. directed that the felling of naval timber should take place only from november 1 to march 15, and during the decrease of the moon, on account of the rapid decay of timber, through the fermentation of its sap, if cut at other seasons. the burying of wood in water, which dissolves out or alters its putrescible constituents, has long been practised as a means of seasoning. the old "resistance" frigate, which went down in malta harbour, remained under water for some months, and on being raised was found to be entirely freed from the dry rot fungus that had previously covered her; similarly, in the ship "eden," the progress of rot was completely arrested by 18 months' submergence in plymouth sound, so that after remaining a year at home in excellent condition she was sent out to the east indies. it was an ancient practice in england to place timber for thrashing-floors and oak planks for wainscotting in running water to season them. whale and other oils have been recommended for the preservation of wood; and in 1737 a patent for the employment of hot oil was taken out by a mr emerson. for the modern processes of preserving timber see timber. dualism (from rare lat. _dualis_, containing two, from _duo_), a philosophical term applied to all theories which attempt to explain facts by reference to two coexistent principles. the term plays an important part in metaphysical, ethical and theological speculation. _in metaphysics._--metaphysical dualism postulates the eternal coexistence of mind and matter, as opposed to monism both idealistic and materialistic. two forms of this dualism are held. on the one hand it is said that mind and matter are absolutely heterogeneous, and, therefore, that any causal relation between them is _ex hypothesi_ impossible. on the other hand is a hypothetical dualism, according to which it is held that mind cannot bridge over the chasm so far as to _know_ matter _in itself_, though it is compelled by its own laws of cause and effect to postulate matter as the origin, if not the motive cause, of its sensations. it follows that, for the thinking mind, matter is a necessary hypothesis. hence the theory is a kind of monism, inasmuch as it confessedly does not assert the existence of matter save as an intellectual postulate for the thinking mind. matter, in other words, must be assumed to exist, though mind cannot know it _in itself_. from this question there emerges a second and more difficult problem. consciousness, it is held, is of two main kinds, sensation and reason. sensation alone is insufficient to explain all our intellectual phenomena; all sensation is momentary and individual (cf. empiricism). how then are we to account for memory and the principles of necessity, similarity, universality? it is argued that there must be in the mind an enduring, primary faculty whereby we retain, compare and group the presentations of sense. this faculty is _a priori_, transcendental, and entirely separate from all the data of experience and sense-perception. here then we have a dualism within experience. the mind is not to be regarded as a sensitized film which automatically records the impressions of the senses. it contains within itself this modifying critical faculty which reacts upon and arranges the sense-given presentations. _in ethics and theology._--in the domain of morals, dualism postulates the separate existence of good and evil, as principles of existence. in theology the appearance of dualism is sporadic and has not the fundamental, determining importance which it has in metaphysics. it is a result rather than a starting-point. the old zoroastrianism, and those christian sects (e.g. manichaeism) which were influenced by it, postulate two contending deities ormuzd and ahriman (good and evil), which war against one another in influencing the conduct of men. so, in christianity, the existence of satan as an evil influence, antagonistic to god, involves a kind of dualism. but generally speaking this dualism is permissive, inasmuch as it is always held that god will triumph over satan in his own time. so in zoroastrianism the dualism is not ultimate, for ahriman and ormuzd are represented as the twin sons of zervana akarana, i.e. limitless time, wherein both will be finally absorbed. the postulate of an evil being arises from the difficulty, at all times acutely felt by a certain type of mind, of reconciling the existence of evil with the divine attributes of perfect goodness, full knowledge and infinite power. john stuart mill (_essay on religion_) preferred to disbelieve in the omnipotence of god rather than forgo the belief in his goodness. it follows from such a view that satan is not the creation of god, but rather a power coeval in origin, over whose activity god has no absolute control. _in theology._--dualism is also used in a special theological sense to describe a doctrine of the nestorian heresy. according to this doctrine the personality of christ is twofold; the divine logos dwells as a distinct personality in the man jesus christ, the union of the two natures being analogous to the relation between the believer and the indwelling holy spirit. _history of the doctrine._--the earliest european thinkers (see ionian school of philosophy) endeavoured to reduce all the facts of the universe to a single material origin, such as fire, water, air. it is only gradually that there appears any recognition of a spiritual principle exercising a modifying or causal influence over inert matter. anaxagoras was the first to postulate the existence of reason ([greek: nous]) as the source of change and progress. yet even he did not conceive this reason as incorporeal; it was in reality only the most highly rarefied form of matter in existence. in plato for the first time we find a truly dualistic conception of the universe. asserting that ideas alone really exist, he yet found it necessary to postulate a second principle of not-being, the groundwork of sensuous existence and of imperfection and evil. herein he identified metaphysics and ethics, combining the good with the truly existent and evil with the non-existent. aristotle rebels against this conception and substitutes the idea of [greek: prote hyle] and development. nevertheless he does not escape from the dualism of form and matter, [greek: nous] and [greek: hyle]. the scholastic philosophers naturally held dualistic views resulting from their extreme devotion to formalism. this blind dualism found its natural consequence in the revolt of the renaissance thinkers, bruno and paracelsus, who asserted the unity of mind and matter in all existence and were the precursors of the more intelligent monism of leibnitz and the scientific metaphysics of his successors. the birth of modern physical science on the other hand in the investigations of bacon and descartes obscured the metaphysical issue by the predominance of the mechanical principles of natural philosophy. they attempted to explain the fundamental problems of existence by the unaided evidence of the new natural science. thus descartes maintained the absolute dualism of the _res cogitans_ and the _res extensa_. spinoza realized the flaw in the division and preferred to postulate behind mind and matter a single substance (_unica substantia_) while leibnitz explained the universe as a harmony of spiritual or semispiritual principles. kant practically abandons the problem. he never really establishes a relation between pure reason and things-in-themselves (_dinge an sich_), but rather seeks refuge in a dualism within consciousness, the transcendental and the empirical. since kant there are, therefore, two streams of dualism, dealing, one with the radical problem of the relation between mind and matter, the other with the relation between the pure rational and the empirical elements within consciousness. to the first problem there is one obvious and conclusive answer, namely that matter in itself is inherently unthinkable and comes within the vision of the mind only as an intellectual presentation. it follows that philosophy is in a sense both dualist and monist; it is a cosmic dualism inasmuch as it admits the possible existence of matter as a hypothesis, though it denies the possibility of any true knowledge of it, and is hence in regard of the only possible knowledge an idealistic monism. it is a self-destructive dualism, a confessedly one-sided monism, agnostic as to the fundamental problem. to the second problem there are two main answers, that of associationism which denies to the mind any _a priori_ existence and asserts that sensation is the only source of knowledge, and that which admits the existence of both transcendental and empirical knowledge.