Anyhow, in the studying I did for that talk, one of the things I started to think is that by focusing on the trivium as developmental stages, we have lost what the trivium actually is. So grammar is the entire body of literature of a culture, historically speaking. The mechanics of writing and phonics and such are included, but that is just the beginning of grammar, which includes history and literature and poetry and more. Dialectic is reasoning within the context of a conversation between co-learners. Rhetoric alone seems to have maintained its original meaning.
This planet, lying between two of much greater mass, has evidently had less material from which to be formed by aggregation; and if we assume--as in the absence of evidence to the contrary we have a right to do--that its beginnings were not much later (or earlier) than those of the earth, then its smaller size shows that it has in all probability aggregated very much more slowly. But the internal heat acquired by a planet while forming in this manner will depend upon the rate at which it aggregates and the velocity with which the 'planetismals' fall into it, and this velocity will increase with its mass and consequent force of gravity. In the early stages of a planet's growth it will probably remain cold, the [[p. 85]] small amount of heat produced by each impact being lost by radiation before the next one occurs; and with a small and slowly aggregating planet this condition will prevail till it approaches its full size. Then only will its gravitative force be sufficient to cause incoming matter to fall upon it with so powerful an impact as to produce intense heat. Further, the compressive force of a small planet will be a less effective heat-producing agency than in the case of a larger one.
During the whole of its early growth, and till it acquired nearly its present diameter, its rate of aggregation was so slow that the planetismals falling upon it, though they might have been heated and even partially liquefied by the impact, were never in such quantity as to produce any considerable heating effect on the whole mass, and each local rise of temperature was soon lost by radiation. The planet thus grew as a solid and cold mass, compacted [[p. 86]] together by the impact of the incoming matter as well as by its slowly increasing gravitative force. But when it had attained to within perhaps 100, perhaps 50 miles, or less, of its present diameter, a great change occurred in the opportunity for further growth. Some large and dense swarm of meteorites, perhaps containing a number of bodies of the size of the asteroids, came within the range of the sun's attraction and were drawn by it into an orbit which crossed that of Mars at such a small angle that the planet was able at each revolution to capture a considerable number of them. The result might then be that, as in the case of the earth, the continuous inpour of the fresh matter first heated, and later on liquefied the greater part of it as well perhaps as a thin layer of the planet's original surface; so that when in due course the whole of the meteor-swarm had been captured, Mars had acquired its present mass, but would consist of an intensely heated, and either liquid or plastic thin outer shell resting upon a cold and solid interior.
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