Concerning the Nature of Things: Six Lectures Delivered at the Royal InstitutionG. Bell, 1925 - 231 pages |
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Page 16 - what is the cause of fluidness? This I conceive to be nothing else but a certain pulse or shake of heat ; for, heat being nothing else but a very brisk and vehement agitation of the parts of a body (as I have elsewhere made probable), the parts of a body are thereby made so loose from one another that they easily move any way and become fluid. That I may explain this a little by a gross similitude, let us suppose a dish of sand set upon some body that is very much agitated and shaken with some quick...
Page 49 - We have to go a step further, and see how, at very slow speeds of approach, they may actually stick together. We have all seen those swinging gates which, when their swing is considerable, go to and fro without locking. When the swing has declined, however, the latch suddenly drops into its place, the gate is held and after a short rattle the motion is all over. We have to explain an effect something like that. When the two atoms meet, the repulsions of their electron shells usually cause them to...
Page 17 - ... twere) sinks to the bottom. Nor can ye make a hole in the side of the dish, but the sand shall run out of it to a level. Not an obvious property of a fluid body, as such, but this does imitate; and all this merely caused by the vehement agitation of the...
Page 46 - ... world. In each there is a nucleus which is positively charged ; round the nucleus are electrons which are units of negative electricity. The positive charge of the nucleus is a multiple of a certain unit charge, equal to the charge on the electron, but of opposite sign. The number of electrons which every atom possesses under normal conditions is an exact balance to the positive charge on the nucleus, so that the atom as a whole is not charged ; its positive and negative charges balance. Whether...
Page 2 - Lucretius, if subdivision were carried out sufficiently, one would come at last to the individual corpuscles or atoms : the word atom being taken in its original sense, something which cannot be cut. There is a mighty difference between the two views. On the one, there is nothing to be gained by looking into the structure of substances more closely, for however far we go we come to nothing new. On the other view, the nature of things as we know them will depend on the properties of these atoms of...
Page 16 - ... millstone turn'd round upon the under stone very violently whilst it is empty; or on a very stiff drum-head, which is vehemently or very nimbly beaten with the drumsticks. By this means the sand in the dish, which before lay like a dull and unactive body, becomes a perfect fluid; and ye can no sooner make a hole in it with your finger, but it is immediately filled up again, and the upper surface of it levelled. Nor can ye bury a light body, as a piece of cork under it, but it presently emerges...
Page 15 - It is motion that keeps them apart; and when we look closely into the matter we find that motion plays a part of first importance in all that we see, because it sets itself against the binding forces that would join atoms together in one lump. In a gas, motion has the upper hand; the atoms are moving so fast that they have no time to enter into any sort of combination with each other: occasionally atom must meet atom and, so to speak, each hold out vain hands to the other, but the pace is too great...
Page 14 - ... entirely ignorant of their mode of action, but we know much more about the rules of combination - that is to say, about the facts of chemistry - than we do about the details of the attractions. However, we need not trouble ourselves about these matters for the present; we have merely to realise that there are forces drawing atoms together. We may now ask why, if there are such forces, the atoms do not all join together into one solid mass? Why are there any gases or even liquids? How is it that...
Page 27 - The piston PP is dropped suddenly from the position indicated by the dotted lines to the position indicated by the full lines : so that the air in the chamber is suddenly chilled by expansion and fog settles on the tracks of the helium atoms shot out by the radium at R.
Page 15 - ... sun because it is in motion round the sun, or, to be more correct, because the two bodies are moving round one another. It is motion that keeps them apart ; and when we look closely into the matter we find that motion plays a part of first importance in all that we see, because it sets itself against the binding forces that would join atoms together in one lump. In a gas, motion has the upper hand ; the atoms are moving so fast that they have no time to enter into any sort of combination with...