XXXV

Among Prerogative Instances I will put in the thirteenth place Instances of Alliance or Union. They are those which mingle and unite natures supposed to be heterogeneous, and marked and set down as such in the received divisions.

Instances of alliance show that operations and effects attributed to some one heterogeneous nature as peculiar to it may belong also to other heterogeneous natures; that this supposed heterogeneity is proved to be not real or essential, but only a modification of a common nature. They are therefore of most excellent use in raising and elevating the understanding from specific differences to genera, and in dispelling phantoms and false images of things, which in concrete substances come before us in disguise. For example, let the nature in question be heat. We are told (and it seems to be a division quite received and authorized) that there are three kinds of heat: the heat of heavenly bodies, the heat of animals, and the heat of fire; and that these heats (especially one of them as compared with the other two) are in their very essence and species — that is to say, in their specific nature — distinct and heterogeneous, since the heat of heavenly bodies and of animals generates and cherishes, while the heat of fire wastes and destroys. We have, therefore, an instance of alliance in that common case, when the branch of a vine is brought within a house where a fire is constantly kept up, and the grapes ripen on it a whole month sooner than they do out of doors; so that the ripening of fruit, even while it hangs on the tree, may be brought about by fire, though such ripening would seem to be the proper work of the sun. From this beginning, therefore, the understanding, rejecting the notion of essential heterogeneity, easily rises to inquire what are in reality those points of difference between the heat of the sun and of fire which cause their operations to be so dissimilar, however they may themselves partake of a common nature.

These differences will be found to be four. The first is that the heat of the sun compared with the heat of fire is far milder and softer in degree; the second is that in quality (at least as it reaches us through the air) it is far moister; the third (and this is the main point) is that it is exceedingly unequal, now approaching and increased, now receding and diminished; which thing chiefly contributes to the generation of bodies. For Aristotle was right in asserting that the principal cause of the generations and corruptions which are going on here on the surface of the earth is the oblique course of the sun through the zodiac; whence the heat of the sun, partly by the alternation of day and night, partly by the succession of summer and winter, becomes strangely unequal. And yet this great man must go on at once to corrupt and deprave what he has rightly discovered. For laying down the law to nature (as his way is), he very dictatorially assigns as the cause of generation the approach of the sun, and as the cause of corruption his retreat; whereas both together (the approach of the sun and his retreat), not respectively, but as it were indifferently, afford a cause both for generation and production; since inequality of heat ministers to generation and corruption, equality to conservation only. There is also a fourth specific difference between the heat of the sun and of fire, and one of very great moment; viz., that the sun operates by gentle action through long spaces of time, whereas the operations of fire, urged on by the impatience of man, are made to finish their work in shorter periods. But if anyone were to set to work diligently to temper the heat of fire and reduce it to a milder and more moderate degree, as is easily done in many ways, and were then to sprinkle and intermix a little moisture; and if above all he were to imitate the heat of the sun in its inequality; and lastly if he could submit to a slow procedure, not indeed corresponding to the operations of the sun, but yet slower than men generally adopt in working with fire; he would speedily get rid of the notion of different kinds of heat, and would attempt to imitate, if not equal or in some cases even surpass the works of the sun by the heat of fire. We have a similar instance of alliance in the revival of butterflies stupefied and half dead with cold, by slightly warming them at a fire. So that you may easily see that fire is no more without the power of giving life to animals than of ripening vegetables. Thus also Fracastorius' celebrated invention of the heated pan with which doctors cover the heads of apoplectic patients who are given over, manifestly expands the animal spirits, compressed and all but extinguished by the humors and obstructions of the brain, and exciting them to motion, just as fire acts on air or water, by consequence quickens and gives them life. Eggs also are sometimes hatched by the heat of fire, which thus exactly imitates animal heat. And there are many instances of the same kind, so that no one can doubt that the heat of fire may in many subjects be modified so as to resemble the heat of heavenly bodies and of animals.

Again, let the natures in question be motion and rest. It appears to be a received division and drawn from the depths of philosophy, that natural bodies either move in circle, or move straight forward, or remain at rest. For there is either motion without limit, or rest at a limit, or progress toward a limit. Now, that perpetual motion of rotation seems to be proper to the heavenly bodies, station or rest seems to belong to the globe of the earth, while other bodies (which they call heavy or light, being indeed placed out of the region to which they naturally belong) are carried toward the masses or congregations of their likes; light bodies upward toward the circumference of the heaven, heavy bodies downward towards the earth. And this is pretty talk.

But we have an instance of alliance in one of the lower comets, which though far below the heaven, nevertheless revolve. And Aristotle's fiction of a comet being tied to or following some particular star has long been exploded, not only because the reason for it is not probable, but because we have manifest experience of the discursive and irregular motion of comets through various parts of the sky.

Again, another instance of alliance on this subject is the motion of air, which within the tropics, where the circles of rotation are larger, seems itself also to revolve from east to west.

Again, another instance would be the ebb and flow of the sea, if it be found that the waters themselves are carried in a motion of rotation (however slow and evanescent) from east to west, though subject to the condition of being driven back twice in the day. For if things be so, it is manifest that that motion of rotation is not limited to heavenly bodies, but is shared also by air and water.

Even that property of light substances, viz., that they tend upward, is somewhat at fault. And on this point a bubble of water may be taken as an instance of alliance. For if there be air under the water it rapidly ascends to the surface by that motion of percussion (as Democritus calls it) by which the descending water strikes and raises the air upward; not by any effort or struggle of the air itself. And when it is come to the surface of the water, then the air is stopped from further ascent by a slight resistance it meets with in the water, which does not immediately allow itself to be separated; so that the desire of air to ascend must be very slight.

Again, let the nature in question be weight. It is quite a received division that dense and solid bodies move toward the center of the earth, rare and light toward the circumference of the heaven, as to their proper places. Now as for this notion of places, though such things prevail in the schools, it is very silly and childish to suppose that place has any power. Therefore philosophers do but trifle when they say that if the earth were bored through, heavy bodies would stop on reaching the center. Certainly it would be a wonderful and efficacious sort of nothing, or mathematical point, which could act on bodies, or for which bodies could have desire, for bodies are not acted on except by bodies. But this desire of ascending and descending depends either on the configuration of the body moved or on its sympathy or consent with some other body. Now if there be found any body which, being dense and solid, does not move to the earth, there is an end of this division. But if

Gilbert's opinion be received, that the earth's magnetic power of attracting heavy bodies does not extend beyond the orb of its virtue (which acts always to a certain distance and no more), and if this opinion be verified by a single instance, in that we shall have got at last an instance of alliance on the subject of weight. But at present there does not occur any instance on this subject certain and manifest. What seems to come nearest to one is that of the waterspouts, often seen in the voyage over the Atlantic Ocean toward either of the Indies. For so great is the quantity and mass of water suddenly discharged by these waterspouts that they seem to have been collections of water made before, and to have remained hanging in these places, and afterward to have been rather thrown down by some violent cause, than to have fallen by the natural motion of gravity. So that it may be conjectured that a dense and compact mass, at a great distance from the earth, would hang like the earth itself and not fall unless thrust down. But on this point I affirm nothing certain. Meanwhile in this and many other cases it will easily be seen how poor we are in natural history, when in place of certain instances I am sometimes compelled to adduce as examples bare suppositions.

Again, let the nature in question be discourse of reason. The distinction between human reason and the sagacity of brutes appears to be a perfectly correct one. Yet there are certain instances of actions performed by animals, by which it seems that brutes too have some power of syllogizing; as in the old story of the crow which, in a time of great drought being half dead with thirst, saw some water in the hollow trunk of a tree, and finding it too narrow to get in, proceeded to drop in a number of pebbles till the water rose high enough for it to drink; and this afterward passed into a proverb.

Again, let the nature in question be visibility. It appears to be a very correct and safe division which regards light as primarily visible, and affording the power of seeing; while color is secondarily visible, and cannot be seen without light, so that it appears to be nothing more than an image or modification of light. And yet there appear to be instances of alliance on either side, namely, snow in great quantities, and the flame of sulphur; in one of which there appears to be a color primarily giving light, in the other a light verging on color.