blue, with their feveral degrees or fhades and mixtures, as green, fcarlet, purple, fea-green, and the reft, come in only by the eyes; all kind of noifes, founds, and tones, only by the ears; the feveral taftes and fmells, by the nofe and palate: And if these organs, or the nerves, which are the conduits to convey them from without to their audience in the brain, the mind's prefence-room (as I may call it), are any of them fo difordered as not to perform their functions, they have no poftern to be admitted by, no other way to bring themselves into view, and be perceived by the understanding. The most confiderable of those belonging to the touch are heat, and cold, and folidity; all the rest confifting almost wholly in the fenfible configuration, as fmooth and rough, or elfe more or lefs firm adhesion of the parts, as hard and foft, tough and brittle, are obvious enough. §2. Few fimple Ideas have Names. I THINK it will be needlefs to enumerate all the particular fimple ideas belonging to each fenfe; nor indeed is it poflible if we would, there being a great many more of them belonging to most of the fenfes than we have names for. The variety of fmells, which are as many almoft, if not more, than fpecies of bodies in the world, do most of them want names. Sweet and flinking commonly ferve our turn for thefe ideas, which in effect is little more than to call them pleafing or difpleafing, though the fmell of a rofe and violet, both fweet, are certainly very diftinct ideas. Nor are the different taftes tl. by our palates we receive ideas of, much better provided with names. Sweet, bitter, four, harfh, and falt, are almost all the epithets we have to denominate that numberless variety of relishes which are to be found diftinct, not only in almost every fort of creatures, but in the different parts of the fame plant, fruit, or animal. The fame may be faid of colours and founds. I fhall therefore, in the account of fimple ideas I am here giving, content myfelf to fet down only fuch as are most material to cur prefent purpofe, or are in themselves lefs apt to be taken notice of, though they are very frequently the ingredients of our complex ideas, amongst which I think I may well account folidity, which therefore I fhall treat of in the next chapter. THE CHAP. IV. OF SOLIDITY. § 1. We receive this Idea from Touch. HE idea of folidity we receive by our touch; and it arifes from the refiftance which we find in body to the entrance of any other body into the place it poffeffes till it has left it. There is no idea which we receive more conftantly from fenfation than folidity. Whether we move or reft, in what pofture loever we are, we always feel fomething under us that supports us, and hinders our farther finking downwards; and the bodies which we daily handle make us perceive, that whilst they remain between them, they do, by an infurmountable force, hinder the approach of the parts of our hands that prefs them. That which thus hinders the approach of two bodies, when they are moving one towards another, I call folidity. I will not difpute whether this acceptation of the word folid be nearer to its original fignification than that which mathematicians ute it in; it fuffices that I think the common notion of folidity will allow, if not justify this use of it; but if any one think it better to call it impenetrability, he has my confent; only I have thought the term folidity the more proper to exprefs this idea, not only becaufe of its vulgar ufe in that fenfe, but also because it carries fomething more of positive in it than impenetrability, which is negative, and is perhaps more a confequence of folidity than folidity itfelf. This of all other feems the idea moft intimately connected with and effential to body, fo as nowhere elfe to be found or imagined but only in matter; and though our fenfes take no notice of it but in maffes of matter of a bulk sufficient to cause a sensation in us, yet the mind having once got this idea from fuch groffer fenfible bodies, traces it farther, and confi ders it, as well as figure, in the minutest particle of matter that can exist, and finds it infeparably inherent in body, wherever or however modified. § 2. Solidity fills Space. THIS is the idea belongs to body, whereby we conceive it to fill space; the idea of which filling of space is, that where we imagine any space taken up by a folid fubftance, we conceive it fo to poffefs it, that it excludes all other folid fubftances, and will for ever hinder any two other bodies, that move towards one another in a ftraight line, from coming to touch one another, unless it removes from between them in a line not parallel to that which they move in. This idea of it the bodies which we ordinarily handle fufficiently furnish us with. §3. Diftinct from Space. THIS refiftance, whereby it keeps other bodies out of the space which it poffeffes, is fo great, that no force, how great foever, can furmount it. All the bodies in the world preffing a drop of water on all fides, will never be able to overcome the refiftance which it will make, as foft as it is, to their approaching one another, till it be removed out of their way; whereby our idea of folidity is diftinguished both from pure space, which is capable neither of refiftance nor motion, and from the ordinary idea of hardness; for a man may conceive two bodies at a distance, fo as they may approach one another, without touching or difplacing any folid thing till their fuperficies come to meet; whereby I think we have the clear idea of space without folidity. For (not to go fo far as annihilation of any particular body) I afk, whether a man cannot have the idea of the motion of one fingle body alone, without any other fucceeding immediately into its place? I think it is evident he can, the idea of motion in one body no more including the idea of motion in another, than the idea of a square figure in one body includes the idea of a fquare figure in another. I do not afk, whether bodies do so exist, that the motion of one body cannot really be without the motion of another; to determine this either way, is to beg the question for or against a vacuum: But my question is, whether one cannot have the idea of one body moved whilst others are at reft? And I think this no one will deny. If fo, then the place it deferted gives us the idea of pure fpace without folidity, whereinto another body may enter, without either refistance or protrufion of any thing. When the fucker in a pump is drawn, the space it filled in the tube is certainly the fame, whether any other body follows the motion of the fucker or no; nor does it imply a contradiction, that upon the motion of one body, another, that is only contiguous to it, fhould not follow it. The neceffity of fuch a motion is built only on the fuppofition that the word is full, but not on the distinct ideas of space and folidity, which are as different as refiftance and not refiftance, protrufion and not protrufion. And that men have ideas of fpace without body, their very difputes about a vacuum plainly demonftrate, as is fhowed in another place. §4. From Hardness. SOLIDITY is hereby alfo differenced from hardness, in that folidity confifts in repletion, and fo an utter exclufion of other bodies out of the space it poffeffes; but hardness, in a firm cohesion of the parts of matter, making up maffes of a fenfible bulk, fo that the whole does not eafily change its figure: And indeed hard and foft are names that we give to things, only in relation to the conftitutions of our own bodies, that being generally called hard by us which will put us to pain fooner than change figure by the preffure of any part of our bodies; and that, on the contrary, foft, which changes the fituation of its parts upon an easy and unpainful touch. But this difficulty of changing the fituation of the fenfible parts amongst themfelves, or of the figure of the whole, gives no more folidity to the hardest body in the world than to the foftest; nor is an adamant one jot more folid than water; for though the two flat fides of two pieces of marble will more eafily approach each other, between which there is nothing but water or air, than if there be a diamond between them, yet it is not that the parts of the diamond are more folid than those of water, or refift more, but because the parts of water being more eafily feparable from each other, they will by a fide-motion be more easily removed, and give way to the approach of the two pieces of marble. But if they could be kept from making place by that fidemotion, they would eternally hinder the approach of thefe two pieces of marble as much as the diamond, and it would be as impoffible by any force to furmount their refiftance, as to furmount the refiftance of the parts of a diamond. The fofteft body in the world will as invincibly refift the coming together of any two other bodies, if it be not put out of the way, but remain between them, as the hardest that can be found or imagined. He that fhall fill a yielding foft body well with air or water, will quickly find its refiftance; and he that thinks that nothing but bodies that are hard can keep his hands from approaching one another, may be pleased to make a trial, with the air inclofed in a football. The experiment, I have been told, was made at Florence with a hollow globe of gold filled with water, and exactly closed, farther fhows the folidity of fo foft a body as water; for the golden globe thus filled being put into a prefs, which was driven by the extreme force of fcrews, the water made itfelf way through the pores of that very close metal, and finding no room for a nearer approach of its particles within, got to the outfide, where it rofe like a dew, and fo fell in drops, before the fides of the globe could be made to yield to the violent compreffion of the engine that squeezed it. § 5. On Solidity depends Impulfe, Reffiance, and Pro trufion. By this idea of folidity, is the extenfion of body diftinguished from the extenfion of fpace; the extenfion of body being nothing but the cohesion or continuity of folid, feparable, moveable parts; and the extenfion of fpace, the continuity of unfolid, infeparable, and immoveable parts. Upon the flidity of body alto depends their mutual impulfe, refiftance, and protrufion. Of pure fpace, then, and folidity, there are feveral (amongst which I confefs myfelf one) who perfuade themselves |