purpofes, and defires, which are the natural language of mankind. An infant may be put into a fright by an angry countenance, and foothed again by fmiles and blandifhments. A child that has a good mufical ear, may be put to fleep or to dance, may be made merry or forrowful, by the modulation of mufical founds. The principles of all the fine arts, and of what we call a fine tafle, may be refolved into connections of this kind. A fine tafte may be improved by reasoning and experience; but if the first principles of it were not planted in our minds by nature, it could never be acquired.

A third clafs of natural figns comprehends thofe which, tho' we never before had any notion or conception of the thing fignified, do fuggeft it, or conjure it up, as it were, by a natural kind of magic, and at once give us a conception, and create a belief of it. Our Author fhewed before, that our fenfations fuggeft to us a fentient being or mind to which they belong: a being which hath a permanent existence, although the fenfations are tranfient and of fhort duration: a being which is still the fame, while its fenfations, and other operations, are varied ten thousand ways a being which hath the fame relation to all that infinite variety of thoughts, purposes, actions, affections, enjoyments, and fufferings, which we are confcious of, or can remember. The conception of a mind is neither an idea of fenfation nor of reflection; for it is neither like any of our fenfations, nor like any thing we are conícious of. The first conception of it, as well as the belief of it, and of the common relation it bears to all that we are confcious of, or remember, is fuggested to every thinking being, we do not know how.

The notion of hardness in bodies, continues he, as well as the belief of it, are got in a fimilar manner; being by an original principle of our nature annexed to that fenfation which we have when we feel a hard body. And fo naturally and neceffarily does the fenfation convey the notion and belief of hardness, that hitherto they have been confounded by the most acute Enquirers into the principles of human nature, although they appear, upon accurate reflection, not only to be different things, but as unlike as pain is to the point of a fword.

It may be obferved, that as the first clafs of natural figns I have mentioned, is the foundation of true philofophy, and the fecond, the foundation of the fine arts, or of tafte; fo the laft is the foundation of common fenfe; a part of human nature which hath never been explained.

I take it for granted, that the notion of hardnefs, and the belief of it, is fift got by means of that particular fenfation, which, as far back as we can remember, does invariably fuggefte

it; and that if we had never had fuch a feeling, we should ne ver have had any notion of hardness. I think it is evident, that we cannot, by reafoning from our fenfations, collect the existence of bodies at all, far lefs any of their qualities. This hath been proved by unanfwerable arguments by the Bishop of Cloyne, and by the Author of the Treatife of human Nature. It appears as evident, that this connection between our fenfations and the conception and belief of external exiftences, cannot be produced by habit, experience, education, or any principle of human nature that hath been admitted by Philofophers. At the fame time it is a fact, that fuch fenfations are invariably connected with the conception and belief of external exiftences. Hence, by all rules of juft reafoning, we muft conclude, that this connection is the effect of our conftitution, and ought to be confidered as an original principle of human nature, till we find fome more general principle into which it may be refolved.'

What our Author has advanced concerning hardness, is fo eafily applicable, not only to its oppofite, foftnefs, but likewife to roughnefs and smoothness, to figure and motion, that he faves himself the trouble of a repetition. All thefe, he fays, by means of certain correfponding fenfations of touch, are prefented to the mind as real external qualities; the conception and the belief of them are invariably connected with the correfponding fenfations, by an original principle of human nature. Their fenfations have no name in any language; they have not only been overlooked by the vulgar, but by Philofophers; or if they have been at all taken notice of, they have been confounded with the external qualities which they fuggeft.

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He goes on to treat of Extenfion, and obferves, that the notion of it is fo familiar to us from infancy, and fo constantly obtruded by every thing we fee and feel, that we are apt to think it obvious how it comes into the mind; but upon a narrow examination, he says, we shall find it utterly inexplicable. It is true we have feelings of touch, which every moment prefent extenfion to the mind; but how they come to do fo, is the queftion; for thofe feelings do no more refemble extenfion, than they resemble juftice or courage: nor can the existence of extended things be inferred from thofe feelings by any rules of reafoning; fo that the feelings we have by touch, can neither explain how we get the notion, nor how we come by the belief of extended things.

What hath impofed upon Philofophers in this matter, we are told, is, that the feelings of touch, which fuggeft primary qualities, have no names, nor are they ever reflected upon. They pals through the mind inftantaneously, and ferve only to intro

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duce the notion and belief of external things, which, by our conftitution, are connected with them. They are natural figns, and the mind immediately pafles to the thing fignified, without making the leaft reflection upon the fign, or obferving that there was any fuch thing. Hence it hath always been taken for granted, that the ideas of extenfion, figure, and motion, are ideas of fenfation, which enter into the mind by the fenfe of touch, in the fame manner as the fenfations of found and imell do by the ear and nose. The fenfations of touch are fo connected by our constitution with the notions of extenfion, figure, and motion, that Philofophers have miftaken the one for the other, and never have been able to difcern, that they were not only distinct things, but altogether unlike. However, if we will reafon diftinétly upon this fubject, we ought to give names to those feelings of touch; we muft accuftom ourfelves to attend to them, and to reflect upon them, that we may be able to disjoin them from, and to compare them with, the qualities fignified or fuggefted by them.The habit of doing this is not to be attained without pains and practice; and till a man hath acquired this habit, it will be impoffible for him to think diftinétly, or to judge right upon this fubject.

Our Author proceeds to make fome reflections in regard to the existence of a material world, and the fyftems of Philofophers concerning the fenfes; after which he goes on to treat of the fenfe of Seeing. As what he advances on this fubject takes up almost two thirds of his work, we must content ourfelves with laying before our Readers a general view of the several points which he difcuffes.

After fome general remarks on the excellence and dignity of the faculty of feeing, he obferves, that there is very little of the knowlege acquired by fight, that may not be communicated to a man born blind. One who never faw the light, may be learned and knowing in every science, even in Optics; and may make discoveries in every branch of philofophy. He may underftand as much as another man, not only of the order, diftances, and motions of the heavenly bodies, but of the nature of light; and of the laws of the reflection and refraction of its rays. He may understand diftinctly, how thofe laws produce the phenomena of the rain-bow, the prifm, the camera obfcura, the magic lanthorn, and all the powers of the microscope and telefcope. This is a fact, we are told, fufficiently attefted by experience.

In order to perceive the reafon of it, continues our Author, we muft diftinguifh the appearance that objects make to the eye, from the things fuggefted by that appearance: and again, in

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the vifible appearance of objects, we muft diftinguish the ap pearance of colour from the appearance of extenfion, figure, and motion. First, then, as to the vifible appearance of the figure, and motion, and extenfion of bodies, I conceive that a man born blind may have a diftinct notion, if not of the very things, at least of something extremely like to them. May not a blind man be made to conceive, that a body moving directly from the eye, or directly towards it, may appear to be at reft? and that the fame motion may appear quicker or flower, according as it is nearer to the eye or farther off, more direct or more oblique? May he not be made to conceive, that a plain furface, in a certain pofition, may appear as a ftraight line, and vary its vifible figure, as its pofition, or the pofition of the eye, is varied? That a circle feen obliquely will appear an ellipfe; and a fquare, a rhombus or an oblong rectangle? Dr. Saunderfon understood the projection of the sphere, and the common rules of perspective; and if he did, he must have understood all that I have mentioned. If there were any doubt of Dr. Saunderfon's understanding these things, I could mention my having heard him fay in converfation, that he found great difficulty in understanding Dr. Halley's demonftration of that propofition, That the angles made by the circles of the fphere, are equal to the angles made by their reprefentatives in the stereographic projection but, faid he, when I laid afide that demonftration, and confidered the propofition in my own way, I faw clearly that it must be true. Another Gentleman, of undoubted credit, and judgment in thefe matters, who had part in this converfation, remembers it diftin&ly.

As to the appearance of colour, a blind man must be more at a lofs; because he hath no perception that resembles it. Yet he may, by a kind of analogy, in part fupply this defect. To thofe who fee, a fcarlet colour fignifies an unknown quality in bodies, that makes to the eye an appearance, which they are well acquainted with, and have often obferved: to a blind man, it fignifies an unknown quality that makes to the eye an appearance which he is unacquainted with. But he can conceive the eye to be varioufly affected by different colours, as the nofe is by different fmells, or the ear by different founds. Thus he can conceive scarlet to differ from blue, as the found of a trumpet does from that of a drum; or as the finell of an orange differs from that of an apple. It is impoffible to know whether a fcarlet colour has the fame appearance to me which it hath to another man; and if the appearances of it to different perfons differed as much as colour does from found, they might never be able to difcover this difference. Hence it appears obvious, that a blind man might talk long about colours diftin&tly and pertinently:

pertinently and if you were to examine him in the dark about the nature, compofition, and beauty of them, he might be able to answer, so as not to betray his defect.

We have feen how far a blind man may go in the knowlege of the appearances which things make to the eye. As to the things which are fuggefted by them, or inferred from them; although he could never difcover them of himfelf, yet he may understand them perfectly by the information of others. And every thing of this kind that enters into our minds by the eye, may enter into his by the ear. Thus, for inftance, he would never, if left to the direction of his own faculties, have dreamed of any fuch thing as light: but he can be informed of every thing we know about it. He can conceive, as diftinctly as we, the minutenefs and velocity of its rays, their various degrees of refrang bility and reflexibility, and all the magical powers and virtues of that wonderful element. He would never of himself have found out, that there are fuch bodies as the fun, moon, and ftars; but he may be informed of all the noble discoveries of Aftronomers about their motions, and the laws of nature by which they are regulated. Thus it appears, that there is very little knowlege got by the eye, which may not be communicated by language to those who have no eyes.'

The diftinction made between the vifible appearances of the objects of fight, and things fuggefted by them, is neceffary, our Author fays, to give us a juft notion of the intention of nature in giving us eyes. If we attend duly to the operation of our minds in the ufe of this faculty, we fhall perceive, that the vifible appearance of objects is hardly ever regarded by us. It is not at all made an object of thought or reflection, but serves only as a fign to introduce to the mind fomething else, which may be diftinctly conceived by thofe who never faw.Thus a book or a chair has a different appearance to the eye, in every different distance and pofition: yet we conceive it to be still the fame; and overlooking the appearance, we immediately conceive the real figure, diftance, and pofition of the body, of which its vifible or perfpective appearance is a fign and indication. A thousand instances might be produced, in order to fhew, that the visible appearances of objects are intended by nature only as figns or indications; and that the mind paffes inftantly to the thing fignified, without making the leaft reflection upon the fign, or even perceiving that there is any fuch thing. It is in a way fomewhat fimilar, that the founds of a language, after it is become familiar, are overlooked, and we attend only to the things fignified by them.

Our Author goes on to tell us, that he cannot entertain the hope of being intelligible to thofe Readers who have not, by