seen bows, the one end of which has been very near to him, and the other at a very great distance.  I have often seen the same thing myself.  I recollect well to have seen the end of a rainbow between myself and a house, or between myself and a bank, not twenty yards distant; and this repeatedly.  But I never saw, what he says he has seen, different rainbows at the same time, intersecting each other.  I never saw coexistent bows, which were not concentric also.  Again, according to the theory, if the sun is in the horizon, the horizon intercepts the lower half of the bow, if above the horizon, that intercepts more than the half, in proportion.  So that generally the bow is less than a semicircle, and never more.  He says he has seen it more than a semicircle.  I have often seen the leg of the bow below my level.  My situation at Monticello admits this, because there is a mountain there in the opposite direction of the afternoon’s sun, the valley between which and Monticello is five hundred feet deep.  I have seen a leg of a rainbow plunge down on the river running through the valley.  But I do not recollect to have remarked at any time, that the bow was more than half a circle.  It appears to me, that these facts demolish the Newtonian hypothesis, but they do not support that erected in its stead by the Abbe.  He supposes a cloud between the sun and observer, and that through some opening in that cloud, the rays pass, and form an iris on the opposite part of the heavens, just as a ray passing through a hole in the shutter of a darkened room, and falling on a prism there, forms the prismatic colors on the opposite wall.  According to this, we might see bows of more than the half circle, as often as of less.  A thousand other objections occur to this hypothesis, which need not be suggested to you.  The result is, that we are wiser than we were, by having an error the less in our catalogue; but the blank occasioned by it, must remain for some happier hypothesist to fill up.

The dispute about the conversion and reconversion of water and air, is still stoutly kept up.  The contradictory experiments of chemists, leave us at liberty to conclude what we please.  My conclusion is, that art has not yet invented sufficient aids, to enable such subtle bodies to make a well defined impression on organs as blunt as ours:  that it is laudable to encourage investigation, but to hold back conclusion.  Speaking one day with Monsieur de Buffon on the present ardor of chemical inquiry, he affected to consider chemistry but as cookery, and to place the toils of the laboratory on a footing with those of the kitchen.  I think it, on the contrary, among the most useful of sciences, and big with future discoveries for the utility and safety of the human race.  It is yet, indeed, a mere embryon.  Its principles are contested; experiments seem contradictory; their subjects are so minute as to escape our senses; and their result too fallacious to satisfy the mind.  It is probably an age too