Графични страници
PDF файл
ePub

though I so much love flowers, and especially the sweet honeysuckle.

Perhaps not ; yet you see, that it mast be so, or you could not smell it. A pound of gold might be so extended as to cover a wire which would surround the globe.

This is wonderful : but how astonishing it is, Father, that those little insects, which you showed me the other day through the microscope, should each of them have distinct parts, the same as the larger animals.. After looking at them, I learnt the pretty lines which you showed me; and when I see any little creature, I always think of them.

Repeat them, if you can ; they afford a very interesting illustration of the divisibility of matter.

FRANK,
" See! each within its little bulk, contains,
A heart, which drives the torrent through its veins ;
Muscles to move its limbs aright, a brain,
And nerves dispos'd for pleasure or for pain :
Eyes to distinguish; sense, whereby to know,
What's good, or bad; is, or is not, its foe."

But, Father, cannot we divide matter till we destroy it?

No: grind a grain or two of sand as much as you please, you do not destroy them ; the particles of which they were composed, still exist : you have divided, but you cannot destroy them.

But when you burn a piece of wood, it is destroyed, is it not?

No: still I must say, divided, but not destroyed. The several parts of which it was composed, are gone off into other forms, but they are not annihilated; that is, they do not cease to be. There is not a single particle of matter less or more now, than there was at the creation of the world.

Things then may be changed, Father, but they cannot be destroyed.

This is the truth, Frank. But a second quality of matter, is impenetrability; by which is meant, that every body fills a certain space equal to its bulk, and which no other body can fill.

Is this true, Father ? When the tea cup appears empty, is it not so ? Is it full of air? And when the tea is poured into it, does it displace the air, and fill up its room ?

Yes; but still though the air be displaced from the tea cup, it occupies another space equal to its bulk. You are now by me ; but if you run to yonder gate, you will displace the air near it ; but still, both you and the air will occupy a space equal to your bulk, or size. I understand you, Father. I see,

that substance of every kind is substance; and, of course, it must, unless you could destroy it, have a place.

B2

Extension, is a third quality of matter by which wo mean, that it exists in different figures and forms, which are long or broad, or of various shapes.

That, Father, is evident, from ourselves, and the trees, and rivers, and fields, and creatures, and the heavens, and the sun, and the moon, and every thing.

It is. As you understand this part of the subject also, I will mention a fourth quality of matter, its inertia,or, the resistance which it makes to any change of state. A stone cannot put itself in motion ; and if it, be put into motion, it is unable to stop itself.

But it is soon stopped.

It is ; by the resistance of the air, or some other cause: it does not stop itself, and it did not put itself in motion; and indeed, it never could have done this. It is true, that matter does move ; but it is equally true, that it is not by its own power;. It is God who gives it motion..

A fifth quality of matter, is attraction. There are two kinds of attraction; the first is, the attraction of cohesion; without this, every thing around us would crumble into pieces. I will break this bough ; there, I have destroyed the attraction of cohesion, which united it together, just in the place where I have brokep it.

When I broke the China cup, sometime ago, Father, then I destroyed the attraction

Yes; and when we saw the plumbers melting their lead at the new house yester. day, they destroyed the cohesion of the particles of metal by fire.

But, Father, can you tell me how this is?

Yes; heat expands every object, and thus it separates the particles of the hardest met. als from each other, and melts them : it is thus, that water, when it boils, expands, and flies away in steam.

Then, Father, when we say, that any thing is hard or soft, do we mean, that the attraction of cohesion is greater in the hard than in the soft substance ?

Certainly. Every object you behold, illustrates the doctrine of the attraction of cohesion, This is also the case with the attraction of gravitation ; by which we understand, the tendency of all bodies to each other. This we constantly witness, as things are always falling to the ground.

Do you know, Father, how rapidly apy body falls to the ground;

Yes ; sixteen feet in the first second of time; three times sixteen in the next second ; five times this distance in the third second ; seven times in the fourth ; and so on regularly, till the body reaches the earth,

When I drop my marbles, do they fall to the ground by the attraction of gravitation ?

Yes; and this is the reason why things stand firmly on the earth in every part of the globe. There are people you know in the islands of the great Southern Ocean, and animals, and rivers, and other things, the same as there are here ; and though they are opposite to us, yet on account of the attraction of gravitation, they are as secure as ourselves.

That is, because every thing naturally falls, or gravitates to the earth.

Certainly : and this gravity acts on bodies, in proportion to the bulk of matter which they contain. Thus a ten times greater force operates on a weight of ten pounds, than on a weight of one; so, all bodies which fall from an equal height, fall with the same swiftness.

How, Father, with the same swiftness :

Yes, if there should be nothing to intercept either of them.

But the top of this sea-weed, which does not weigh an ounce, and a pound weight, could not come to the ground at the same moment, Father, could they ?

No; because the sea-weed presents a broader surface to the air ; and so it meets with more resistance than the pound weight.

But would they fall at the same instant if there were no air ?

« ПредишнаНапред »