« PreviousContinue »
SCIENCE AND GENERAL HISTORY.
1.-CONVERSATION ON THE ESSENTIAL PROPERTIES OF
Sub'til-ty, No....... .....subtilis. De-fined', v...............finis. Em'a-nat-ing, part......Inanāre. Ex-ten’sion, n...... .....tenděre. E-mit'ting, part......... mittěre. Im-pen-e-tra-bil'i-ty, n..penetrāre. Dis-solved', part. .......solvěre. Di-vis-i-bil'i-ty, n........ dividěre. De-duc'tions, no, .........ducěre. Mo-bil'i-ty, n............. mõbilis. Im-pelling, part........ pellěre. In-er'tia, n...
Ulti-mate, adj............ultimus. In-de-struc-ti-bisi ty, n..struěre. At-ten-u-a'-tion, n...... tenuis. At-trac'tion, no...... ..trahere. Par'ti-cle, no ...... pars.
GREEK. Mole'cules, N.....
...moles. Spher'i-cal, adj..........sphaira. Def'i-nite, adj. ..finis. Hy-poth’e-sis, n.........hupo, thesis. Dif-fused', part..........funděre. Atoms, n. ........
.temno. Mag'ni-fies, v.......
magnus, Sy-non'y-mous, adj.....onoma.
Father. Do you understand, my dears, what philosophers ' mean when they make use of the word Matter?
Em. Are not all things which we see and feel composed of matter?
Fa. Everything which is the object of our senses is composed of matter, differently modified or arranged: but, in a philosophical sense, it is defined to be an extended, impenetrable, inactive, and moveable substance.
1 The essential properties of matter, then stated here are, Extension, Impenetrability, Divisibility, Inertia, and Mobility, to which may be added Figure, or form, which is the result of extension, for we cannot conceive that a body has length, breadth, and thickness, without its having some kind of figure.- Indestructibility that is the property by which matter never ceases to exist,- Attraction, the pro perty by which bodies tend towards each other.
Ch. If by extension is meant length, breadth, and thickness, matter, undoubtedly, is an extended substance. Its impenetrability also is manifest by the resistance it makes to the touch.
Em. And the other properties nobody will deny ; for all material objects are, of themselves, without motion, which I suppose is what is meant by inactive : and yet, it may be readily conceived that, by the application of a proper force there is no body which cannot be moved, whence it may be said to be moveable. But I remember, Papa, that you told us something strange about the divisibility of Matter, which you said might be continued without end.
Fa. I did, some time ago, mention this as a curious and interesting subject; and this is a very fit time for me to explain it.
Ch. Can matter indeed be infinitely divided ? For I suppose that this is what is meant by a division without end.
Fa. Difficult as this may at first appear, yet it seems very capable of proof. Can you imagine a particle of matter to be so small as not to have an upper and an under surface?
Ch. Certainly not; every portion of matter, however minute, must have two surfaces at least; and then I see that it follows of course that it is divisible ; for the upper surface could be separated from the under one, and this again be repeated to infinity.
Fa. Your conclusion is just; matter is by some considered to be infinitely divisible, and many arguments besides yours have been advanced in support of that opinion ; nevertheless it is impossible to imagine that the molecules of which you conceive matter to consist, can be composed of anything else than certain definite but excessively minute indivisible atoms, and this is the opinion now adopted by most philosophers, although it is perhaps a question which is incapable of satisfactory solution. Em. But you were kind enough to say that
would mention to us some remarkable instances of the minute division of matter.
Fa. A few years ago a lady spun a single pound of wool into a thread 168,000 yards long: and Mr. Boyle mentions that two grains and a half of silk were spun into a thread of 300 yards in length. If a pound of silver, which contains 5760 grains, and a single grain of gold, be melted together,
the gold will be equally diffused throughout the whole mass of silver ; so that if one grain of the mass be dissolved in a liquid called aqua fortis, which is crude nitric acid, the gold will fall to the bottom. By this experiment it is evident that a grain may be divided into 5761 visible parts, for only the 576 lst part of the gold is contained in a single grain of the mass.
Gold-beaters can spread a grain of gold into a leaf containing fifty square inches ; and this leaf may be readily divided into 500,000 parts ; each of which is visible to the naked eye. By the help of a microscope, which magnifies the area or surface of a body 100 times, the 100th part of each of these becomes visible ; that is, the fifty millionth part of a grain of gold will be visible, or a single grain of that metal may be divided into fifty million visible parts. But the gold which covers the silver wire, used in making what is called gold lace, is spread over a much larger surface ; yet it preserves, even if examined by a microscope, a uniform appear
It has been calculated that one grain of gold, under these circumstances, would cover a surface of nearly thirty square yards.
In the gilding of buttons, five grains of gold, which is applied as an amalgam with mercury, is allowed to each gross, so that the coating deposited must amount to the 110,000th part of an inch in thickness.
The natural divisions of matter are still more surprising. In odoriferous bodies, such as lavender-water, camphor, musk, asafætida, and scents of various kinds, a wonderful subtilty of parts is perceived : for though they are perpetually filling a considerable space with odoriferous particles, yet these bodies lose but a very small part of their weight or quantity in a great length of time. One grain of musk has been known to perfume a room for the space of twenty years. In the perfume emanating from a flower, how diminutive must be the particles that reach the olfactory nerves of the nose when we smell them, and which are themselves invisible and cause no sensible diminution to the bulk of the plant.
The Lycoperdon, or puff-ball, is a fungus growing in the form of a tubercle, which, being pressed, bursts, emitting a dust so fine and so light, that it floats through the air with the appearance of smoke. Examined under the microscope, this dust, which is the seed of the plant, appears under the form of globules of an orange colour, perfectly rounded, and in diameter about the fiftieth part of a hair ; so that if this calculation be correct, and a globule were taken having the diameter of a hair, it would be one hundred and twenty-five thousand times as great as the seed of the lycoperdon.
In Leslie's “Natural Philosophy"we read that millions of the insect Monas gelatinosa, found among duck-weed, are sporting about in one drop of liquid: and that the Vibrio undula, found on the same plant, is computed to be ten thousand million times smaller than a hemp seed. Now, if it be admitted that these little animals are possessed of organized parts, such as a heart, stomach, muscles, veins, arteries, &c., and that they are possessed of a complete system of circulating fluids, similar to what is found in larger animals, we seem to approach to an idea of the infinite divisibility of matter. It has indeed been calculated that a particle of the blood of one of these animalcules is as much smaller than a globe onetenth of an inch in diameter, as that globe is smaller than the whole earth. Nevertheless, if these particles be compared with the particles of light, it is probable that they would be found to exceed them in bulk as much as mountains exceed single grains of sand.
There is a very familiar example in the sweetening of tea, a small lump of sugar extending its influence throughout the entire cup-full; and in one drop how diminutive must be the portion of sugar.
Again, a drop of port-wine put into a tumbler of water will tinge the whole mass, so that one drop of it can contain but a very minute portion of the wine.
A single grain of copper dissolved in nitric acid, will give a blue tint to three pints of water: by which the copper is attenuated at least one hundred million times.
I might enumerate many other instances of the same kind; but these, I doubt not, will be sufficient to convince you into what very minute parts matter is capable of being divided ; and with these we will close our present conversation.
Fa. Now, my dear Charles, let me be the questioner, after our several conversations relating to the same subject, in order to find if you have entered into the spirit of the information you have received, and made such deductions as may be useful to you.
Ch. Most willingly, Papa.
Fa. You have learned, in this latter conversation, that matter is philosophically defined to be an extended, impene, trable, inactive, and moveable substance. How do
understand these terms ?
Ch. Extension is that principle of matter by which it occupies a part of space. Impenetrability implies a property by which two bodies cannot exist in the same place at the same time. Inactive and moveable apply to a body which resists, in any degree, a force impelling it to a change of state, with regard to motion and rest; but which may be moved, if sufficient force be applied to it.
Em. Of what shape are the ultimate particles of the generality of natural solids?
Fa. It is the opinion of most philosophers I have read that they are, for the most part, spherical; but many different ideas have been formed as to the nature of matter.
What is your opinion, now, after our conversation on the subject?
Ch. Matter is said to be infinitely divisible ; and many are the arguments advanced in support of that hypothesis ; yet, it can only be divisible as being composed of atoms; but an atom cannot be divided by any natural means.
Em. Is there, then, any difference between matter and body?
Fa. Yes: for although bodies are composed of matter, those terms are not strictly synonymous. Bodies are capable of being divided ; because the atoms of which they are composed may, by various means, be separated. The attenuation of gold on wire, of which mention has been made, is not perhaps, strictly speaking, a division of matter, but of body.
Ch. Are bodies of themselves inactive, or inert ?
Fa. They must be so until they are forced into action. It has been well observed, in elucidation of this fact, that a tranquil pool of water is inert; but when made to fall on a mill-wheel, it becomes an immensely active power.
Joyce's Scientific Dialogues.
1. Of what is every thing which we see as not to have an upper and an under and feel composed ?
surface ? 2. How is matter defined ?
6. If it has these, must it still be divisi. 3. What are the essential properties of ble ? matter, and say what you understand by 7. In short do not some philosophers each?
conceive that it can be divided without 4. Can matter be divided into very mi. end ? nute particles ?.
8. What length of thread did the lady 5. Can you think of a particle so small / spin out of a single pound of wool ?