DECLARATION.

than is necessary for daily mills, provided that water flows from a somewhat higher slope.

This method of a mill is indeed new not to all, but I think to many, since in most places there is no need for it; yet there are many of this kind in Toulouse and other places. The water-wheel of this, which is to the south, is parallel to the millstone, into which water flows from the east, although it does not matter at all from which side it flows. And furthermore, it is an advantage of this machine that it is manufactured at a cheaper price, since there is no use for a drum in it: the rest are evident from the figure.

PROP. XXIX.

A new form of musical organ, whose metallic strings, plucked by fingers and plectrum, produce a varied and pleasant concert, tempered by equal modes, by which the sounds of lyres and trumpets are in a certain way reproduced.

Know that the effect of the work is thus not explained by me.

PROP. XXX.

An artifice never before seen, by which, with a small hand of men, masses of columns and obelisks may be transported from the stones, for both the beauty and the perpetuity of royal buildings.

The whole force of this machine is in the alternation of the winches. For there are three winches around which the rope is gathered so that its end is in the southern winches: but so that you may better perceive it, the stone to be transported is the northern one, moved by rollers rolling themselves around an axis like a wheel; on the face of the assembly of these rollers is a winch, then, in the south there is also another winch next to that wooden southern [beam] itself, in which are the first ends of the ropes; this is immovable, as is the other which is the middle one, distant from it by 13 palms, in which are the other ends of the aforementioned ropes. Now, truly, with these two drawing the stone toward themselves, much force is conferred by the other: for when the same rope is wound around it, it aids both winches, whence they easily draw the stony mass, which may be seen by experience.

PROP. XXXI.

A new machine for lifting and carrying huge burdens into carts through passable places, and that, if not clearly with the speed with which it is usually done, at least with less expense and labor, both of horses and of men.

The artifice of this machine depends on the method of the previous one, but two things must be considered here, for the weight is lifted and [then] carried. Therefore let us see what pertains to the first.

From east to west inclines a derrick, from whose top hang two quadrilateral pyramids whose bases are parallel; in each of them are many pulleys, thirteen in the upper, twelve in the lower, established at the angles of the pyramids as appears in the figure placed to its side. Around these pulleys a rope is wound in the same way as in the aforementioned winches; this is tied at one extremity to a ring distant 1 measure and 6 palms from the top of the derrick at the southern foot, but at the other extremity to a winch distant from the top 1 measure and 19 palms. This winch, however, is aided by a triple-pulley block set at the end of that septenary, and is that instrument which we commonly call an endless screw, whose figure is in the 39th figure inclining toward the angle of the west and north; in this triple-pulley block there is so much force that it cannot be explained in words. The rest that cling to the apex of the lower pyramid are hands and hooks for seizing the burden.

Furthermore, so that this same burden may be carried away, there are three carts, of which the southern one is of four wheels, but the others of only two. In the last part of the southern cart is a winch around which is revolved a rope tied to the other two carts, one of which is in the northern line, but the other is distant a little from it; in the end of these two is such an instrument as is seen here in the void at the angle of the west and north, so that the carts do not recede. Now with them proceeding and the winch aiding, the burden is lightly carried: which is the proposal.

PROP. XXXII.

A kind of artifice suitable for exporting merchandise and towing ships against a river, with no wind blowing, with fewer horses and less expense than is usually the case.