Theater of Machines, Part 2

and libration leveling is the first beginning of all water conduction, whether for gushing fountains or for the drive of incessant motion of various mills and similar artificial water structures, which are driven by the fall and rising or flowing forward of the water. And such leveling or libration may take place from the location to which we wish to lead such water, or at the place where it originates, by sighting through the instruments along a straight line, as is shown in the following figure with the two Greek letters δ and φ, or with the two Latin letters B and C. Where then such a water level or chorobates leveling instrument is placed and fastened, a plumb line is placed upon it, as is common practice among workmen to level the gutters and channels, and to measure every plane, as denoted in the following figure with D and E, or to be seen at both places of the water level with P and Q. Through such an instrument a long line may be drawn to conduct the water, according to the guideline or through leveling, as such a decline for the fall of the water may be done most appropriately. As stated, the sighting may be directed from the origin of the springs to the place to which one wishes to conduct the water, or from the latter toward the springs, as the situation of the location itself will require. In the following figure, both sights are denoted with θ. When the point of such a sight is marked, the distance from one location to the other is measured with the instrument of a long graduated straightedge, which is specifically arranged for surveying and is commonly called a rod; you can see this denoted in the following figure with N and N. Now, when the space is measured from one point to another,

Libration, a beginning of water conduction.