Patent for a new and improved windmill. This design consists in "[t]he combination of the horizontal wind-wheel, the semi-cylindrical case partly inclosing the same and independently revoluble, the case having the notches in its upper side, the vane having the shaft or port whose lower end forms the upper pivot for the said case, and the lever having its inner end fast to the vane shaft or port, and adapted to engage the said notches, and thereby cause the case to expose any desired area of the wheel to the wind" (lines 89-99).