The works of Francis Bacon, lord chancellor of England.

414 THOUGHTS ON THE NATURE OF THINGS.
permeates the whole, come into view, till a visible Of the cause of Motion in Fire-arms, which has been
break or divulsion of continuity takes place. hitherto investigated only in part, and that part
Again, we observe, if we happen to bend and comparatively unimporlant.
compress between the thumb and forefinger the
two ends of a wire, or bit of cane, or the harder IX.
part of a pen, (or similar bodies which unite The theory of fire-arms-of a motion so powerflexibility with a certain degree of elasticity,) they ful and so remarkable, is imperfect, and, in the
anon spring from the hand. The cause of which more important part, defective. For it is said in
motion is evidently discernible not to be in the explanation that the gunpowder, after having been
extremities compressed by the fingers, but in the converted into flame and vo]atilized, expands and
middle part, which is the seat of forcible pressure, occupies more space; whence it follows, that as
to relieve itself from which, the motion comes into two bodies cannot exist in the same space, otherplay. And in this instance it is clearly shown, I wise a jumbling of their dimensions would ensue,
that the alleged cause of motion, the impulsion or the elementary form be destroyed, or a preterof the air, is inadmissible. For here there is no natural arrangement of the internal parts of the
concussion to let in a rush of air. This is also body be the effect, (for this is what they say,) that
proved by a slight experiment, when we press the impeding body is ejected or broken. And
the fresh and smooth ball of a plum, drawing the what they say contains something. For this tenfingers gradually together, and in this manner let dency is both an affection of matter, and an ingreit go. For in that instance also compression is dient in the motion itself. Yet they err in this,
substituted for percussion. But the most conspi- that in their over hasty way of determining, they
cuous effect of this interior motion is in the revo- jump at once to the necessary consequence of the
lotions and gyrations of missiles while flying. dilatation of abody, and do not accurately consider
The missiles, indeed, proceed onwards, but they what comes first in the order of nature. For that
make their progression in spiral lines, that is, by the substance of the gunpowder, after having been
straight-lined and rotatory motion together, and converted into flame, must occupy a larger space,
indeed this curvilinear motion is so fleet, and at is doubtless a thing of necessity; but that the subthe same time so easy, and somehow so familiar stance of the gunpowder should be inflamed at
to things, as to excite a doubt in my mind whe- all, and that so instantaneously, is not determined
ther it does not depend on some higher principle. by a like necessity, but depends on an antagonism,
Yet I think that the cause of this fact is no other and comparative force of motions. For there is
than the same we are now handling. For the not a doubt, that the compact and heavy body
concussion of the body occasions an excessive which is expelled or dislodged by this motion,
impetus in all its parts and particles, to effect in offers considerable resistance before it gives way,
some way or other their extrication and freedom. and, if it happen to be the stronger, is victorious;
The body, therefore, not only acts and flies forth that is to say, the flame, in that case, does not cast
in a straight line, but strives to move from every out the ball, but the ball stifles the flame. If,
point in it at once, and, therefore, whirls round; therefore, instead of gunpowder, you take sulfor in both ways it somewhat relieves itself of its phur, asphaltum, or the like, bodies which are also
impuise. Now this, which in the harder solids quickly inflammable, and (as the closeness of
is a somewhat recondite and latent property, is in particles in bodies hinders ignition) reduce them
the softer ones evident, and, so to speak, palpable. to a grain like gunpowder, mixing up with it a
For as wax, and lead, and similar soft bodies, small quantity of the ashes of the juniper, or some
when struck with a mallet, give way not only in other very combustible wood; yet, should the
the line of percussion, but laterally every way; nitre be wanting, that rapid and powerful motion
so, in like manner, hard or resisting bodies move does not follow: the motion to perfect inflammain a straight line and periphery at once. For the tion is impeded and fettered by the resisting body,
retrocession of soft bodies in their substance, and so that it cannot fully expand and take effect.
of hard ones in their place, is the same in its prin- For, besides the motion of inflammation, which
ciple, as is evidently seen in the structure of the chiefly arises from the sulphureous part of the
soft body, and in the affection of the hard one, gunpowder,there is yet another powerful and vioexhibited in its flight and volant path. Meantime lent motion in the case. This is caused by the
let none think that besides this motion, (which is crude watery ether, which is extricated from the
the cardinal point,) I do not ascribe a certain de- nitre in part, but chiefly from the charcoal, and
gree of effect to the conveyance of the air, which which not only itself dilates, as exhaled essences
is capable of assisting, obstructing, modifying, are wont to do, on the application of heat, but at
and regulating the principal motion; for its power the same time (which is the principal circumis far from being inconsiderable. And this doe- stance) by a motion of extreme rapidity, flies off
trine of violent or mechanical motion (which has and breaks forth from the heat and flame, thus
been hitherto unknown) is, as it were, the foun- distending and opening passages for the inflam
tain-head of practical mechanics. mation to follow. Of this motion we see the