the unphilofophical fpectator to a foreigner, who only fees the external part of the building. From fo fuperficial a view, it is evident he can obtain but a very unfatisfactory idea of the skill and contrivance of the GREAT DESIGNER. To form a more accurate conception, to perceive it's beauties, to difcover it's conveniences, it is neceffary to enter the building, to view each apartment separately, to compare the convenience of every room fingly, with the fymmetry and elegance of the whole.

In the fame manner the beauties of nature ftrike our view: we find curiofity allured by a variety of objects, animals, vegetables, minerals air, water, and fire: all put on different appearances to please, affift, or aftonish us: but in order to come at a knowledge of their nature, we must apVOL. III. proach

B

The investigation of properties in the fenfe here used, confifts in examining the phenomena belonging to the fubftance in queftion; and afcending from one effect to another, till you arrive at fomething which is a cause agreeable to the foregoing definition; that is, which evidently and clearly arifes from the idea of the fubftance confidered, and which cannot be feparated from it without annihilating the fubftance, or being infeparable therefrom by any human conception.

It has been usual to reckon among the properties of MATTER, impenetrability, extenfion, figure, divifibility, hardness, inertia, motion, attraction, and repulfion, I know of no other which have a right to be examined, as affecting the senses, which, as I have often obferved, can alone conftitute the science of phyfics. Let us then compare the ideas of these properties with the preceding definition, and you will foon fee that the three laft mentioned must be excluded from the clafs of properties fo defined, and cannot with strict propriety be termed the characters of materiality.

Impenetrability, confidered as expreffing that two particles of what conftitutes matter (whatever it may be) cannot exift at the fame time in the fame place, fo long as one retains it's place it must neceffarily exclude the other, is undoubtedly a phyfical axiom; the contrary propofition would be a contradiction.

The phyfical world would vanish from the eyes of the understanding, and we should no longer have any notion thereof, if impenetrability, as here confidered, was not an effential property of matter. There could be no existence of this fubftance, unless the idea of impenetrability immediately arofe from it. As it is neither the existence of the fubflance, nor the cause of it's existence, that we are consider

ing, but it's properties, there can be no doubt of this firft principle.

For as foon as matter exifts, it is impenetrable; this is the first thing which conftitutes it's existence as matter, that is, as a part of the phyfical world, an object of the five fenfes.

Every thing therefore, which is deduced from the impenetrability of matter, will be the refult of what I have called a primary caufe, and is fubordinate to nothing elfe but the cause of the existence of matter.

Extenfion is another property of the fame kind; it is indeed included in the idea of impenetrability, when it is confidered with refpect to fpace, namely, that two particles of matter cannot exift at the fame time in the fame place; they are therefore extended, that is, they occupy a certain portion of space. Extenfion is therefore an effentially conftituent property of matter.

Figure is another property that neceffarily flows from the preceding definition, or rather from the existence of matter itself. Whatever is material, must have figure or thape; every finite extenfion is terminated or comprehended under fome figure.

So far there cannot be two modes of thinking concerning the properties of matter, unless fome other fpecies of being is meant by the word matters in which cafe it would not belong to our physical world, that which affects our fenfes. But the remaining properties require a closer examination.

Divifibility. If this expreffion be confined to the poffibility of conceiving that every atom of matter may be indefinitely divided by a fufficient power; that is to fay, that when confidered as extended, a right and a left may be always feparated by the mind, and by a fufficient power could

B 3

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