"nature but that of God; this being is the "infinite force which unites all the parts of "matter, an immenfe fpring which is in "continual action." Vol. i. p. 277. It is evident, however, that this philofopher confidered the ultimate particles of matter as fomething different from any thing belonging to the Deity. But his principles, purfued to their proper extent, would have been the fame with thofe of Mr. Baxter.

SECT.

SECTION II.

Of IMPENETRABILITY, as afcribed to

Matter.

S philofophers have given too little to matter, in divefting it of all powers, without which I prefume it has been proved that no fuch fubftance can exift, fo it equally follows, from the plain rules of philofophizing above laid down, that they have afcribed too much to it, when they have advanced that im penetrability is one of its properties. Because, if there be any truth in late difcoveries in philofophy, refiftance is in moft cafes caused by fomething of a quite different nature from any thing material, or folid, viz. by a power of repulfion acting at a distance from the body to which it has been fuppofed to belong, and in no cafe whatever can it be proved that refiftance is occafioned by any thing elfe.

Now if refiftance, from which alone is derived the idea of impenetrability, is in moft cafes certainly, caufed by powers, and in no café certainly by any thing elfe, the rules of philofophizing oblige us to suppose, that the caufe of all refiftance is repulfive power, and in no cafe whatever the thing that we have hitherto improperly termed folid, or impene

trable matter.

As all refiftance can differ only in degree, this circumftance can only lead us to the fuppofition of a greater or lefs repulfive power, but never to the fuppofition of a cause of refiftance intirely different from fuch a power. This would be exceedingly unphilofophical. To judge in this manner, is to judge altogether without, nay really contrary to evidence. But I come to the facts themselves, which no philofopher will pretend to con

trovert.

When I prefs my hand against the table, as was mentioned above, I naturally imagine that the obftacle to its going through the table is the folid matter of which it confifts but a variety of philofophical confiderations. demonstrate, that it generally requires a much greater power of preffure than I can exert to bring my fingers into actual contact with the table. Philofophers know that, notwithstanding their feeming contact, they are actually kept at a real distance from each other, by powers of repulfion common to them both, Alfo, electrical appearances fhew that a confiderable weight is requifite to bring into contact, even links of a chain hanging freely in the air; they being kept asunder by a repulfive power belonging to a very fmall furface, fo that they do not actually touch, though they are fupported by each other.

I have myself, as will be seen in the account of my electrical experiments, (fee Hiftory of Electricity, p. 702.) endeavoured to af

certain

certain the weight requifite to bring a number of pieces of money, lying upon one another, into feeming contact, or fo near to one another only as the particles that compose the fame continued piece of metal, and I found it to be very confiderable. These, however, are fuppofed by philofophers not to be in actual contact, but to be kept at certain distances from each other by powers of resistance within the fubftance itself. That the component particles of the hardest bodies do not actually touch one another, is demonftrable from their being brought nearer together by cold, and by their being removed farther from each other by heat. The power, fufficient to overcome thefe internal forces of repulfion, by which the ultimate particles of bodies are prevented from coming into actual contact, is what no perfon can pretend to compute. The power, requisite to break their cohesion, or to remove them from the sphere of each other's attraction, may, in fome measure, be estimated; but this affords no data for ascertaining the force that would be neceffary to bring them into actual contact, which may exceed the other almost infinitely.

Mr. Melville has fhewn, from optical confiderations, fee Hiftory of Discoveries relating to Vision, &c. p. 454, that a drop of water rolls upon a cabbage leaf without ever coming into actual contact with it; and indeed all the phenomena of light are moft remarkably un

fa

favourable to the hypothesis of the folidity or impenetrability of matter.

When light is reflected back from a body on which it seems to ftrike, it was natural to fuppofe that this was occafioned by its impinging against the folid parts of the body; but it has been demonftrated by Sir Ifaac Newton, that the rays of light are always reflected by a power of repulfion, acting at fome distance from the body. Again, when part of a beam of light has overcome this power of repulfion, and has entered any transparent fubftance, it goes on in a right line, provided the medium be of an uniform denfity, without the leaft interruption and without a fingle particle being reflected, till it comes to the oppofite fide; having met with no folid particles in its way, not even in the denfeft tranfparent fubftances, as glass, crystal, or diamond; and when it is arrived at the oppofite fide, it is folely affected by the laws of attraction and repulfion. For with a cer`tain angle of incidence, the greatest part, or the whole of it, will be drawn back into the folid body, without going on into the air, where it would feem that there would have been lefs obstruction to its paffage.

Now thefe facts feem to prove, that fuch dense bodies as glafs, cryftal and diamonds, have no folid parts, or fo very few, that the particles of light are never found to impinge upon them, or to be obftructed by them. And certainly till fome portion of light can be

fhewn