The natural spirit is generated in the liver, the seat of digestion, "there where our nourishment is administered"; it then passes to the heart, and manifests itself as the spirit of life; from thence it passes to the brain, where it is the animal spirit—"spirit animate" Rossetti calls it—dwelling in the brain.
In the brain there are three ventricles or chambers, the foremost being the "cell fantastike" of the "Knight's Tale," the second the logistic, and the third the chamber of memory, where "memory, the warder of the brain," keeps watch over the passage of the spirit into the "sinews" of moving. Into the foremost cell come all the perceptions of sight, hearing, etc., and thus we have the opportunity for
"Fantasy,
That plays upon our eyesight,"
to freak it on us. The pedant, Holofernes, in Love's Labour's Lost, characteristically puts the origin of his good things in the ventricle of memory.
As a specimen of the physical science of the time the Editor gives extracts from the chapter on light.
The introduction of extracts enough to give some idea of the mediaeval astronomy would have made such large demands on the patience of the reader that the Editor has decided with some regret to omit them altogether. The universe is considered to be a sphere, whose centre is the earth and whose circumference revolved about two fixed points. Our author does not decide the nice point in dispute between the philosophers and the theologians, the former holding that there is only one, the latter insisting on seven heavens-the fairy, ethereal, olympian, fiery, firmament, watery, and empyrean.
The firmament, that
"Majestical roof, fretted with golden fire,"
is the part of heaven in which the planets move. It carries them round with it; it governs the tides; it stood with men for the type of irresistible regularity. Each of the planets naturally has a motion of its own, contrary in direction to that of the firmament, which was from east to west. All the fixed stars move in circles whose centre is the centre of the universe, but the courses of the planets (among which the moon is reckoned) depend on other circles, called eccentric, since their centre is elsewhere. Either the centre or the circumference of the circle in which the planet really moves is applied to the circumference of the eccentric circle, and in this way all the movements of the planets are fully explained. Our author is sorely puzzled to account for the existence of the watery heavens above the fiery, they being cold and moist, but is sure from scriptural reasons that they are there, and ventures the hypothesis that their presence may account for the sluggish and evil properties of Saturn, the planet whose circle is nearest them.
Having considered the simpler substances, those composed of pure elemental forms, and those resembling them—the meteors—we turn to the perfect compounds, those which have assumed substantial forms, as metals, stones, etc. Our author retains the Aristotelian classification—earthy, and those of other origin, as beasts, roots, and trees. Earths may be metals or fossils; metals being defined as hard bodies, generated in the earth or in its veins, which can be beaten out by a hammer, and softened or liquefied by heat; while fossils include all other inanimate objects.