level in jets and fountains. Without vouching for the great effects said to be produced by these machines, we will describe two, as necessary to give a clear notion of the value of these conceits, and as specimens of the ingenious absurdities, which, under the name of Air Engines, were recommended even by experienced engineers about this period. The machines themselves, under another form, are to be found in the Spiritalia. The book from which they are extracted in their present shape was one of some reputation in its day, and many years after its publication it was thought worthy of being translated into English. The translation went through two editions.*

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The Sixth Figure represents a Very subtil engine to raise Water by means of the Sun ;" which, according to its inventor, "hath great effect in hot places, as in Spain and Italy; because in those places the sun shines almost always with great heat, espe cially in the summer." And they are to be constructed after this manner :

You must have four vessels of copper, (in our engraving we have only shewn two, n, n,) well soldered round about, each of which must be about a foot square, and eight or nine inches high. A pipe, s s, is placed on each vessel, having other pipes, w, w, attached to it, reaching almost to its bottom. A

"New and useful Inventions for Water Works: a work both useful and delightful for all sorts of people; translated into English by John Leak." The plates appear to have been those used in the French edition.

sucker, or valve, 2, is placed in the middle of the pipes, made and placed so that, when the water springs out of the vessels, it may open, and being gone forth, may shut again. You must also have another pipe, a, a, with small pipes, o, o, rising upwards at the bottom of these vessels, and also a sucker (or valve e) to the end of which there is a pipe m, which descends into the water in the cistern r. Το the copper vessels n, n, there shall also be vent-holes X, X. So placing the engine in a place where the sun may shine upon it, pour water into the vessels n, n, by the holes a, to about a third part of their content; the air with which they were previously filled will pass out by the passages. Afterwards you must stop all these passages; "and then the sun shining upon the engine shall make an expression because of the heat, which causeth the water to rise from all the vessels by the pipes w w, and pass forth by the valve ≈; and when there shall be a great quantity of water run forth by the violence of the heat of the sun, then the valve z shall return; and after the heat of the day is passed, and the night shall come, the vessels, to shun vacuity, shall draw up the water of the cistern by the pipe a, o, m, and shall fill the vessels as they were before, so long as there is any water in the cistern."

But, continues the translator, if you desire to raise the water five or six feet high, "the foregoing engine cannot raise it if the sun does not shine with great violence." "To increase the force of the Sun," he proposes to improve the "Subtil Engine" by forming the copper vessels, as shewn in the Seventh Figure, where A, A, are burning glasses well fitted into the