Форум вопросов и ответов

the two qualities do not coincide; phlegm, for instance, is tractile but not squeezable, and [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] a sponge squeezable but not tractile.
Some things are malleable, like copper. Some are not, like stone and wood. Things are malleable when their surface can be made to [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] move (but only in part) both downwards and sideways with one [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] and the same blow: when this is not possible a body is not malleable. All malleable bodies are impressible, but not all impressible bodies are malleable, [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] e.g. wood, though on the whole the two go together. Of squeezable things some [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] are malleable and some not: wax and mud are malleable, wool [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] is not. Some things are fissile, e.g. wood, some are not, [Ссылки могут видеть только зарегистрированные пользователи. Зарегистрироваться...] e.g. potter’s clay. A thing is fissile when it is apt to divide in advance of the instrument dividing it, for a body is said to split when it divides to a further point than that to which the dividing instrument divides it and the act of division advances: which is not the case with cutting. Those bodies which cannot behave like this are non-fissile. Nothing soft is fissile (by soft I mean absolutely soft and not relatively: for iron itself may be relatively soft); nor are all hard things fissile, but only such as are neither liquid nor impressible nor comminuible. Such are the bodies that have the pores along which they cohere lengthwise and not crosswise.
Those hard or soft solids are apt to be cut which do not necessarily either split in advance of the instrument or break into minute fragments when they are being divided. Those that necessarily do so and liquids cannot be cut. Some things can be both split and cut, like wood, though generally it is lengthwise that a thing can be split and crosswise that it can be cut. For, a body being divided into many parts fin so far as its unity is made up of many lengths it is apt to be split, in so far as it is made up of many breadths it is apt to be cut.
A thing is viscous when, being moist or soft, it is tractile. Bodies owe this property to the interlocking of their parts when they are composed like chains, for then they can be drawn out to a great length and contracted again. Bodies that are not like this are friable. Bodies are compressible when they are squeezable and retain the shape they have been squeezed into; incompressible when they are either inapt to be squeezed at all or do not retain the shape they have been squeezed into.
Some bodies are combustible and some are not. Wood, wool, bone are combustible; stone, ice are not. Bodies are combustible when their pores are such as to admit fire and their longitudinal pores contain moisture weaker than fire. If they have no moisture, or if, as in ice or very green wood, the moisture is stronger than fire, they are not combustible.
Those bodies give off fumes which contain moisture, but in such a form that it does not go off separately in vapour when they are exposed to fire. For vapour is a moist secretion tending to the nature of air produced from a liquid by the agency of burning heat. Bodies that give off fumes give off secretions of the nature of