things can be both broken and comminuted, others admit only one or the other. Wood, for instance, can be broken but not comminuted,Billy Smith Tröjor, ice and stone can be comminuted but not broken, while pottery may either be comminuted or broken. The distinction is this: breaking is a division and separation into large parts,CG Menn Carson Parka, comminution into parts of any size, but there must be more of them than two. Now those solids that have many pores not communicating with one another are comminuible (for the limit to their subdivision is set by the pores), but those whose pores stretch continuously for a long way are breakable, while those which have pores of both kinds are both comminuible and breakable.
Some things, e.g. copper and wax,Esa Tikkanen Tröjor, are impressible, others, e.g. pottery and water, are not. The process of being impressed is the sinking of a part of the surface of a thing in response to pressure or a blow,Belstaff Lea Jackor, in general to contact. Such bodies are either soft,Dame Moncler Gresselle, like wax, where part of the surface is depressed while the rest remains, or hard,NHL Mens Chicago Blackhawks Black Hoodie, like copper. Non-impressible bodies are either hard, like pottery (its surface does not give way and sink in), or liquid, like water (for though water does give way it is not in a part of it, for there is a reciprocal change of place of all its parts). Those impressibles that retain the shape impressed on them and are easily moulded by the hand are called ‘plastic’; those that are not easily moulded,Brandon Saad Tröjor, such as stone or wood, or are easily moulded but do not retain the shape impressed, like wool or a sponge,Nashville Predators Tröjor, are not plastic. The last group are said to be ‘squeezable’. Things are ‘squeezable’ when they can contract into themselves under pressure, their surface sinking in without being broken and without the parts interchanging position as happens in the case of water. (We speak of pressure when there is movement and the motor remains in contact with the thing moved, of impact when the movement is due to the local movement of the motor.) Those bodies are subject to squeezing which have empty pores-empty, that is,Mike Gartner Tröjor, of the stuff of which the body itself consists-and that can sink upon the void spaces within them, or rather upon their pores. For sometimes the pores upon which a body sinks in are not empty (a wet sponge, for instance, has its pores full). But the pores, if full, must be full of something softer than the body itself which is to contract. Examples of things squeezable are the sponge, wax, flesh. Those things are not squeezable which cannot be made to contract upon their own pores by pressure, either because they have no pores or because their pores are full of something too hard. Thus iron,Walt Tkaczuk Tröjor, stone, water and all liquids are incapable of being squeezed.
Things are tractile when their surface can be made to elongate, for being drawn out is a movement of the surface, remaining unbroken, in the direction of the mover. Some things are tractile, e.g. hair, thongs, sinew,Patrick Sharp Tröjor, dough, birdlime, and some are not, e.g. water, stone. Some things are both tractile and squeezable,Woolrich Parka, e.g. wool; in other cases
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