Cut batts to length by setting the top of the batt into the space and cutting against the bottom plate with a sharp utility knife. Leave an extra 1/2 in. of length for a tighter fit. We're using unfaced batts that are sized to friction-fit into standard stud spaces (either 16-in. or 24-in. on-center studs).
History of Windmills. The Persians seem to have been the first to develop windmills (between 500 and 900 A.D.). Sails had long been used to move ships at sea, but the Persians converted the wind for use in grinding grain.
The first known documented design is also of a Persian windmill, this one with vertical sails made of bundles of reeds or wood which were attached to the central vertical shaft by horizontal struts (see Figure 1a). A 19th Century American approximation of this panemone device is shown at the left (Figure 1b).