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SECT. II.

OF DILATATIONS CAUSED BY SIMPLE INTROSUSCEPTION,
OR THE ADMISSION OF ONE BODY INTO

THE PORES OF ANOTHER.

ADMONITION.

IT would not have been difficult for us, to have reduced the following scattered history, to a better order, and method; and to have ranged similar instances by themselves: but we avoided this exactness for two reasons; first, because many of the instances are of a doubtful nature, and bear relation to several things: whence an exact method, in this case, would either cause repetition, or be apt to deceive. Secondly, the principal reason of our rejecting an exact method at present is, because we would have the work lye open to every man's industry and imitation. But if this collection of instances should have been disposed in any artificial, and extraordinary method; many, doubtless, would have despaired of performing any thing equal to this enquiry. We, therefore, direct, both by our own example and admonition, that every one in procuring and proposing instances, would use his own judgment, memory, and convenience. It is sufficient to

have the enquiry proceed by writing, and not by memory, (which indeed would be ridiculous, in such a multitude of instances,) so that it may be afterwards brought to perfection by the light of induction.* And it must be well remembered, that in this work, we only collect alms and tribute from the senses, for the treasury of the sciences; without proposing examples for the illustration of axioms; but endeavouring after experiments for the formation of axioms. We shall not, however, be wholly regardless of all arrangement in our instances, but place them so as they may afford light to each other.

UNCONNECTED HISTORY.

No wonder if the dilatation of a body ensues upon the introsusception of another body; since. this is plainly an augmentation or addition; though not a genuine rarifaction. But where the body, thus received within the pores of another, is of the pneumatical kind; as air or spirit; or if it be a tangible body, that slides gradually in, and slowly insinuates itself; this is commonly

* The directions and examples delivered in the second part of the Novum Organum, should be well remembered through the course of the author's particular enquiries; as being what himself had a constant regard to. And we are persuaded, that one half of the use and excellence of his enquiries, is not perceived by the generality of readers, for want of attending to this intimation.

accounted rather a tumefaction than an addition.

Tensile or extendible bodies, as bladders, bellows, &c. are inflated and distended by the entire body of the air; so as to become hard, and capable of being struck, tossed, and projected. And a bubble of water is like a bladder; but for its fragility and tenderness.

Liquors poured from on high, out of one vessel into another, or strongly agitated with a spoon, the wind, the breath, &c. are mixed in along with the air; and thus raised into froth: but soon afterwards, they subside and shrink into less space; the air escaping again, as the little bubbles of the froth break away.

Children, for diversion, make castles of bubbles, by blowing with a pipe into soapy water; which thus becoming somewhat tenacious, a very small quantity of water is made to possess a large space, by the air received within it.

But it is not found that flame can thus be mixed, and made frothy with air, by the inflation of bellows, or other external agitation; so as to constitute a mixed body of flame and air, like to froth; which is a mixture of air and liquor.

On the contrary, it is certain that by internal mixture in a body, before it is set on fire, a mixed body may be made of air and flame: for gun

powder has uninflammable parts from the nitre, and, its inflammable parts principally from the sulphur; whence the flame of gunpowder becomes whiter or paler than other flames ;* tho' that of sulphur alone be bluish; insomuch that the flame of gunpowder may be justly compared to a most expansive froth, or a kind of a fiery wind, composed of flame and air.†

But as froth is a body compounded of air and liquor, so are all powders composed of air and the small parts of the pulverized body: whence they differ from froths, only as contiguous differ from continuous bodies. For the great bulk of them is caused by the air; which distends, or sets the parts of the body at a distance; as appears from the second and third table above laid down.t

There are tumefactions in the bellies, and other parts of animals, arising from flatulency, and an aqueous humour collected within; as in the case of the tympany, dropsy, and the like.

* Except that of camphire, and certain artificial mixtures, as in the compositions of the stars for sky-rockets, &c.

+ The more intimately the thing is considered, or rather, the more experiments are made to give a proper information therein; as by the analysis of nitre, gunpowder, &c. the more just the comparison may, perhaps, appear. * Sect. I.

There is a kind of pigeon, which shrinking its head within its neck, pouts and swells considerably.

In the action of respiration, the lungs alternately expand and contract, while they receive and discharge the air, like a pair of bellows.

The breasts of pregnant females swell, and grow turgid, from the milky humour contained within them.

The penis of the male is greatly dilated, in bulk, upon erection.

Observe the breadth of the pupilla of either eye in a looking-glass, then close the other eye; and you will perceive the pupilla of the open eye manifestly dilated: the spirits that served for both eyes, now flowing into one.

The cracks and fissures of bowls, and the like materials of wood, being contracted by dryness, are filled up and consolidated, by lying for awhile in water; and receiving it within their pores.

There is a kind of fungus growing upon a tree, and called by the name of jews-ears, that being put into water swells exceedingly;* which wool and sponge do not. And so much for the intro

* Especially if boiled in water; where they swell to five

or six times their own dimensions, when dry.

+

Let the number of these instances be augmented.

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