Conversations on Natural Philosophy, in which the Elements of that Science are Familiarly Explained

by Mrs. Marcet; Thomas P. Jones

Mrs. B. The odour or smell of a body is part of the body itself, and is produced by very minute particles or exhalations which escape from the odoriferous bodies. It would be impossible that you should smell the lavender water, if particles of it did not come in actual contact with your nose.

Emily. But when I smell a flower, I see no vapour rise from it; and yet I perceive the smell at a considerable distance.

Mrs. B. You could, I assure you, no more smell a flower, the odoriferous particles of which did not touch your nose, than you could taste a fruit, the flavoured particles of which did not come in contact with your tongue.

Emily. That is wonderful indeed; the particles then, which exhale from the flower and from the lavender water, are, I suppose, too small to be visible?

Mrs. B. Certainly: you may form some idea of their extreme minuteness, from the immense number which must have escaped in order to perfume the whole room; and yet there is no sensible diminution of the liquid in the phial.

Emily. But the quantity must really be diminished?

Mrs. B. Undoubtedly; and were you to leave the bottle open a sufficient length of time, the whole of the water would evaporate and disappear. But though so minutely subdivided as to be imperceptible to any of our senses, each particle would continue to exist; for it is not within the power of man to destroy a single particle of matter: nor is there any reason to suppose that in nature an atom is ever annihilated.

Emily. Yet, when a body is burnt to ashes, part of it, at least, appears to be effectually destroyed: look how small is the residue of ashes in the fire place, from all the fuel which has been consumed within it.

Mrs. B. That part of the fuel, which you suppose to be destroyed, evaporates in the form of smoke, and vapour, and air, whilst the remainder is reduced to ashes. A body, in burning, undergoes no doubt very remarkable changes; it is generally subdivided; its form and colour altered; its extension increased: but the various parts, into which it has been separated by combustion, continue in existence, and retain all the essential properties of bodies.

Emily. But that part of a burnt body which evaporates in smoke has no figure; smoke, it is true, ascends in columns into the air, but it is soon so much diffused as to lose all form; it becomes indeed invisible.