[Plate 45], [fig. 5] represents this System—which is founded on the idea of deadening oscillatory motions at sea, by connecting the bodies to be thus guarded, with a stream of flowing liquid, the horizontal motions of which must be subject to laws very different from those which rule vibrating bodies merely suspended.
The fluid used in this Machine (as oil, water, mercury, &c.) is to be pumped up by appropriate mechanism, from the vessel into which it flows at x, into a vessel placed a little above z; and to be let out by the cock y, through a kind of strainer s, of sufficient collective area to supply, with ease, the descending column C. The vessel and tube C D are made as thin and light as possible: and the upper part, which is spherical, is inclosed in and suspended by the universal joint a b c, like those used to suspend other bodies, as a compass, &c. Moreover, the areas, at different heights, of the tube C D, are made in the inverse ratio of the velocities of the spouting fluid, at each given depth—so as to leave it but little tendency to press either outward or inward, while thus obeying the law of gravity. By these means, then, I think no vibrating motion will be excited in the falling column: but that the liquid will continue to flow perpendicularly, so as to preserve (nearly) the quietude of the vessel C D, and of any mirror or instrument it may be wished to keep in a given position, by connecting it with the perpendicular line thus obtained.
I repeat, however, that I know not how far these methods may go towards obtaining an artificial horizon, for astronomical uses. Indeed, I fear they will fall short in this respect—but I think them still worth trying, even for these—but especially for the purposes to which I have already alluded. And, if success crowns this publication, to the degree I am led to anticipate, I will not always leave so rich a question, in this doubtful predicament.
OF
A FIRE-ESCAPE,
On a retarding Principle.
This is a recollection from the specification of a Patent which I took out above thirty years ago, and in which I huddled together as many objects as a child would like to see in a box of play things. I perhaps acted, then, according to the words of a French proverb—“abondance de bien ne nuit pas;” but in so doing, I fell into the charybdis of another French proverb—“qui trop embrasse, mal étreint,” (a wide embrace cannot be a strong one) and in so doing, paved the way to much litigation—which happily did not occur.
