When I would represent this series of internal phenomena, or, in common language, adventures of travel, only internally, I dispose all at my pleasure; I stop, or travel faster; I take steps of a hundred leagues, and pass immediately from one point to another, and I experience none of those inconveniences which render the reality fatiguing. I am in a world where I am master. I command, and the coach is ready, the driver on his box, the postilion in his saddle; and I fly as borne on the wings of the wind. Beautiful landscapes, barren lands, gigantic mountains, and plains whose boundaries join the heavens, all pass before my eyes with wonderful rapidity. Tired of the land, I embark upon the lofty deep; I see the angry waves, and hear, amid their roaring and dashing against the ship, the voice of the captain giving his orders. I see the sailors work the ship; I speak with the passengers, and roam through the cabins; and yet perceive no offensive smell, and neither feel the qualms of sea-sickness, nor observe them in others. 27. If purely internal sensations, especially when they proceed from external sensations, be indeed mutually connected, their connection is not such that it may not be modified in a thousand ways. When we think of the Obelisk of the Place de la Concorde, its fountains and statues, are very naturally presented to us; so, also, are the Palace of the Tuileries, and that of the Chamber of Deputies, the Madeleine, and the Champs-Elysées; but we can, by an act of the will, change the scene; and if we choose we may transfer the Obelisk to the Place du Carrousel, and admire the effect it produces there, until, satisfied with the operation, we restore it to its granite base, or think no more of it. But with sight, or the external phenomenon, we should in vain strive to perform such manœuvres; everything keeps its place, or, at least, seems to; and the sensations are bound together with bands of iron. One comes after the other, and we cannot pass by any. The mere observation, then, of what passes within us reveals the existence of two wholly distinct orders of phenomena: in the one, everything, or almost everything, depends upon our will; in the other, nothing. In the one, the phenomena have certain mutual relations, very variable, however, and to a great extent subject to our fancy; in the other, they are dependent upon each other, and are produced only under certain conditions. We cannot see, if we do not open the blinds so as to allow the light to enter. Here the phenomena of blinds and sight are necessarily connected; but they are not always so; for we may open them at night, and yet not see; and then we require another auxiliary phenomenon, which is, artificial light. We cannot, if we would, change this law of dependence.