when, on my travels, or walks, or hunting-excursions, I have passed days and nights between the cliffs in the mountain forests. On such occasions a conceit occurred to me, which I give you as nothing better, but which, however, I cannot get rid of, as indeed, generally, such conceits are, of all things, most difficult to get rid of. I altogether look upon it as a truth; and so I will now give utterance to it, especially as I have already so often had occasion to prove the indulgence of my friends.
When we look at the mountains, either closely or from a distance, and see their summits above us, at one time glittering in the sunshine, at another enveloped in mist, swept round with strong clouds, or blackened with showers, we are disposed to ascribe it all to the atmosphere, as we can easily with the eye see and discern its movements and changes. The mountains, on the other hand, with their glorious shapes, lie before our outward senses immovable. We take them to be dead, because they are rigid; and we believe them to be inactive, because they are at rest. For a long while, however, I cannot put off the impulse to ascribe, for the most part, to their imperceptible and secret influence the changes which are observable in the atmosphere. For instance, I believe that the mass of the earth generally, and therefore, also, in an especial way, its more considerable continents, do not exercise a constant and invariable force of attraction, but that this attractive force manifests itself by a certain pulse, which, according to intrinsic, necessary, and probably, also, accidental external causes, increases or decreases. Though all attempts by other objects to determine this oscillation may be too limited and rude, the atmosphere furnishes a standard both delicate and large enough to test their silent operations. When this attractive force decreases never so little, immediately the decrease in the gravity, and the diminished
