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dry heat, and resort to things that are refrigerant, with an inward warmth, and virtue of cherishing.

Experiment solitary touching weight.

789. WEIGH iron and aqua fortis severally; then dissolve the iron in the aqua fortis, and weigh the dissolution; and you shall find it to bear as good weight as the bodies did severally: notwithstanding a good deal of waste by a thick vapour that issueth during the working; which sheweth that the opening of a body doth increase the weight. This was tried once or twice, but I know not whether there were any error in the trial.

Experiment solitary touching the super-natation of bodies.

790. TAKE of aqua fortis two ounces, of quicksilver two drams, for that charge the aqua fortis will bear, the dissolution will not bear a flint as big as a nut-. meg: yet, no doubt, the encreasing of the weight of water will encrease its power of bearing; as we see brine, when it is salt enough, will bear an egg. And I remember well a physician, that used to give some mineral baths for the gout, etc. and the body, when it was put into the bath, could not get down so easily as in ordinary water. But it seemeth the weight of the quicksilver more than the weight of a stone, doth not compense the weight of a stone more than the weight of the aqua fortis.

Experiment solitary touching the flying of unequal bodies in the air.

791. LET there be a body of unequal weight, as of wood and lead, or bone and lead, if you throw it from you with the light end forward, it will turn, and the weightier end will recover to be forwards; unless the body be over-long. The cause is, for that the more dense body hath a more violent pressure of the parts from the first impulsion; which is the cause, though heretofore not found out, as hath been often said, of all violent motions; and when the hinder part moveth

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swifter, for that it less endureth pressure of parts, than the forward part can make way for it, it must needs be that the body turn over: for, turned, it can more easily draw forward the lighter part. Galilæus noteth it well, that if an open trough wherein water is, be driven faster than the water can follow, the water gathereth upon an heap towards the hinder end, where the motion began, which he supposeth, holding confidently the motion of the earth, to be the cause of the ebbing and flowing of the ocean; because the earth over-runneth the water. Which theory, though it be false, yet the first experiment is true. As for the inequality of the pressure of parts, it appeareth manifestly in this; that if you take a body of stone or iron, and another of wood, of the same magnitude and shape, and throw them with equal force, you cannot possibly throw the wood so far as the stone or iron. Experiment solitary touching water, that it may be the medium of sounds.

792. It is certain, as it hath been formerly in part touched, that water may be the medium of sounds. If you dash a stone against a stone in the bottom of the water, it maketh a sound. So a long pole struck upon gravel in the bottom of the water maketh a sound. Nay, if you should think that the sound cometh up by the pole, and not by the water, you shall find that an anchor let down by a rope maketh a sound: and yet the rope is no solid body whereby the

sound can ascend.

Experiment solitary of the flight of the spirits upon odious objects.

793. ALL objects of the senses which are very offensive, do cause the spirits to retire: and upon their flight, the parts are, in some degree, destitute; and so there is induced in them a trepidation and horror. For sounds, we see that the grating of a saw, or any very harsh noise, will set the teeth on edge, and make all the body shiver. For tastes, we see that in the taking of a potion or pills, the head and the neck

shake. For odious smells, the like effect followeth, which is less perceived, because there is a remedy at hand by stopping of the nose; but in horses, that can use no such help, we see the smell of a carrion, especially of a dead horse, maketh them fly away, and take on almost as if they were mad. For feeling, if you come out of the sun suddenly into a shade, there followeth a chilness or shivering in all the body. And even in sight, which hath in effect no odious object, coming into sudden darkness, induceth an offer to shiver.

Experiment solitary touching the super-reflection of echos.

794. THERE is in the city of Ticinum in Italy, a church that hath windows only from above: it is in length an hundred feet, in breadth twenty feet, and in height near fifty; having a door in the midst. It reporteth the voice twelve or thirteen times, if you stand by the close end-wall over-against the door. The echo fadeth, and dieth by little and little, as the echo at Pont-Charenton doth. And the voice soundeth as if it came from above the door. And if you stand at the lower end, or on either side of the door, the echo holdeth; but if you stand in the door, or in the midst just over-against the door, not. Note, that all echos sound better against old walls than new; because they are more dry and hollow.

Experiment solitary touching the force of imagination, imitating that of the sense.

795. THOSE effects which are wrought by the percussion of the sense, and by things in fact, are produced likewise in some degree by the imagination. Therefore if a man see another eat sour or acid things, which set the teeth on edge, this object tainteth the imagination. So that he that seeth the thing done by another, hath his own teeth also set on edge. So if a man see another turn swiftly and long, or if he look upon wheels that turn, himself waxeth turn-sick.

So if a man be upon an high place without rails or good hold, except he be used to it, he is ready to fall: for imagining a fall, it putteth his spirits into the very action of a fall. So many upon the seeing of others bleed, or strangled, or tortured, themselves are ready to faint, as if they bled, or were in strife.

Experiment solitary touching preservation of bodies.

796. TAKE a stock-gilly-flower, and tie it gently upon a stick, and put them both into a stoop-glass full of quicksilver, so that the flower be covered: then lay a little weight upon the top of the glass that may keep the stick down; and look upon them after four or five days; and you shall find the flower fresh, and the stalk harder and less flexible than it was. If you compare it with another flower gathered at the same time, it will be the more manifest. This sheweth, that bodies do preserve excellently in quicksilver; and not preserve only, but by the coldness of the quicksilver indurate; for the freshness of the flower may be merely conservation; which is the more to be observed, because the quicksilver presseth the flower; but the stiffness of the stalk cannot be without induration, from the cold, as it seemeth, of the quicksilver.

Experiment solitary touching the growth or multiplying of metals.

797. IT is reported by some of the ancients, that in Cyprus there is a kind of iron, that being cut into little pieces, and put into the ground, if it be well watered, will increase into greater pieces. This is certain, and known of old, that lead will multiply and increase, as hath been seen in old statues of stone which have been put in cellars; the feet of them being bound with leaden bands; where, after a time, there appeared, that the lead did swell; insomuch as it hanged upon the stone like warts.

Experiment solitary touching the drowning of the more base metal in the more precious.

798. I CALL drowning of metals, when that the baser metal is so incorporate with the more rich, as it can by no means be separated again; which is a kind of version, though false: as if silver should be inseparably incorporated with gold: or copper and lead with silver. The ancient electrum had in it a fifth of silver to the gold, and made a compound metal, as fit for most uses as gold, and more resplendent, and more qualified in some other properties; but then that was easily separated. This to do privily, or to make the compound pass for the rich metal simple, is an adulteration or counterfeiting: but if it be done avowedly, and without disguising, it may be a great saving of the richer metal. I remember to have heard of a man skilful in metals, that a fifteenth part of silver incorporated with gold will not be recovered by any water of separation, except you put a greater quantity of silver to draw to it the less; which, he said, is the last refuge in separations. But that is a tedious way, which no man, almost, will think on. This should be better inquired and the quantity of the fifteenth turned to a twentieth; and likewise with some little additional, that may further the intrinsic incorporation. Note, that silver in gold will be detected, by weight, compared with the dimension; but lead in silver, lead being the weightier metal, will not be detected, if you take so much the more silver as will countervail the over-weight of the lead.

Experiment solitary touching fixation of bodies."

799. GOLD is the only substance which hath nothing in it volatile, and yet melteth without much difficulty. The melting sheweth that it is not jejune, or scarce in spirit. So that the fixing of it is not want of spirit to fly out, but the equal spreading of the tangible parts, and the close coacervation of them: whereby they have the less appetite, and no means at all to issue forth. It were good therefore to try,

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