Thoughts on Man [132]
very readily, and without the least opposition, to transmit the magnetic effluvia, and easily to admit quicksilver into its pores, and to let water pass through it. From all which we may conclude, that gold has more pores than solid parts, and by consequence that water has above forty times more pores than parts. And he that shall find out an hypothesis, by which water may be so rare, and yet not capable of compression by force, may doubtless, by the same hypothesis, make gold, and water, and all other bodies, as much rarer as he pleases, so that light may find a ready passage through transparent substances[43]."
[43] Newton, Optics, Book II, Part III, Prop. viii.
Again: "The colours of bodies arise from the magnitude of the particles that reflect them. Now, if we conceive these particles of bodies to be so disposed among themselves, that the intervals, or empty spaces between them, may be equal in magnitude to them all; and that these particles may be composed of other particles much smaller, which have as much empty space between them as equals all the magnitudes of these smaller particles; and that in like manner these smaller particles are again composed of others much smaller, all which together are equal to all the pores, or empty spaces, between them; and so on perpetually till you come to solid particles, such as have no pores, or empty spaces within them: and if in any gross body there be, for instance, three such degrees of particles, the least of which are solid; this body will have seven times more pores than solid parts. But if there be four such degrees of particles, the least of which are solid, the body will have fifteen times more pores than solid parts. If there be five degrees, the body will have one and thirty times more pores than solid parts. If six degrees, the body will have sixty and three times more pores than solid parts.
And so on perpetually[44]."
[44] Ibid.
In the Queries annexed to the Optics, Newton further suggests an opinion, that the rays of light are repelled by bodies without immediate contact. He observes that:
"Where attraction ceases, there a repulsive virtue ought to succeed. And that there is such a virtue, seems to follow from the reflexions and inflexions of the rays of light. For the rays are repelled by bodies, in both these cases, without the immediate contact of the reflecting or inflecting body. It seems also to follow from the emission of light; the ray, so soon as it is shaken off from a shining body by the vibrating motion of the parts of the body, and gets beyond the reach of attraction, being driven away with exceeding great velocity. For that force, which is sufficient to turn it back in reflexion, may be sufficient to emit it. It seems also to follow from the production of air and vapour: the particles, when they are shaken off from bodies by heat or fermentation, so soon as they are beyond the reach of the attraction of the body, receding from it and also from one another, with great strength; and keeping at a distance, so as sometimes to take up a million of times more space than they did before, in the form of a dense body."
Newton was of opinion that matter was made up, in the last resort, of exceedingly small solid particles, having no pores, or empty spaces within them. Priestley, in his Disquisitions relating to Matter and Spirit, carries the theory one step farther; and, as Newton surrounds his exceedingly small particles with spheres of attraction and repulsion, precluding in all cases their actual contact, Priestley is disposed to regard the centre of these spheres as mathematical points only. If there is no actual contact, then by the very terms no two particles of matter were ever so near to each other, but that they might be brought nearer, if a sufficient force could be applied for that purpose. You had only another sphere of repulsion to conquer; and, as there never is actual contact, the whole world is made up of one sphere of repulsion after another, without the possibility of ever arriving at an end.
"The
[43] Newton, Optics, Book II, Part III, Prop. viii.
Again: "The colours of bodies arise from the magnitude of the particles that reflect them. Now, if we conceive these particles of bodies to be so disposed among themselves, that the intervals, or empty spaces between them, may be equal in magnitude to them all; and that these particles may be composed of other particles much smaller, which have as much empty space between them as equals all the magnitudes of these smaller particles; and that in like manner these smaller particles are again composed of others much smaller, all which together are equal to all the pores, or empty spaces, between them; and so on perpetually till you come to solid particles, such as have no pores, or empty spaces within them: and if in any gross body there be, for instance, three such degrees of particles, the least of which are solid; this body will have seven times more pores than solid parts. But if there be four such degrees of particles, the least of which are solid, the body will have fifteen times more pores than solid parts. If there be five degrees, the body will have one and thirty times more pores than solid parts. If six degrees, the body will have sixty and three times more pores than solid parts.
And so on perpetually[44]."
[44] Ibid.
In the Queries annexed to the Optics, Newton further suggests an opinion, that the rays of light are repelled by bodies without immediate contact. He observes that:
"Where attraction ceases, there a repulsive virtue ought to succeed. And that there is such a virtue, seems to follow from the reflexions and inflexions of the rays of light. For the rays are repelled by bodies, in both these cases, without the immediate contact of the reflecting or inflecting body. It seems also to follow from the emission of light; the ray, so soon as it is shaken off from a shining body by the vibrating motion of the parts of the body, and gets beyond the reach of attraction, being driven away with exceeding great velocity. For that force, which is sufficient to turn it back in reflexion, may be sufficient to emit it. It seems also to follow from the production of air and vapour: the particles, when they are shaken off from bodies by heat or fermentation, so soon as they are beyond the reach of the attraction of the body, receding from it and also from one another, with great strength; and keeping at a distance, so as sometimes to take up a million of times more space than they did before, in the form of a dense body."
Newton was of opinion that matter was made up, in the last resort, of exceedingly small solid particles, having no pores, or empty spaces within them. Priestley, in his Disquisitions relating to Matter and Spirit, carries the theory one step farther; and, as Newton surrounds his exceedingly small particles with spheres of attraction and repulsion, precluding in all cases their actual contact, Priestley is disposed to regard the centre of these spheres as mathematical points only. If there is no actual contact, then by the very terms no two particles of matter were ever so near to each other, but that they might be brought nearer, if a sufficient force could be applied for that purpose. You had only another sphere of repulsion to conquer; and, as there never is actual contact, the whole world is made up of one sphere of repulsion after another, without the possibility of ever arriving at an end.
"The