The construction of the Buckeye engine, which is also of this type, is such that the travel of the valve on the back of the main valve is always the same, no matter what the cut off may be. Then this engine makes use of our second proposition as a means of effecting the cut off, viz., by advancing the eccentric. You will readily observe that anything that will cause the cut off valve to reach a certain point earlier in the stroke will bring about an earlier cut off as it hastens everything all around. This is the plan pursued in the Buckeye, in which the governor, of the shaft type, turns the eccentric forward or back according as the load demands. Then, in addition, the valve is balanced partially, the attempt not being made to produce an absolutely balanced valve, on the ground that there should be friction enough to keep the surfaces bright and to prevent leakage. The most perfect valve will, of course, be entirely balanced under all conditions of pressure so as to move with perfect ease. With the riding cut off valve in connection with the plain slide valve, this is not accomplished, and it does not matter whether it is partially unbalanced to prevent leakage or not, the fact that it is not entirely balanced prevents it reaching the ideal valve. [Illustration: Fig. 5] This valve, Fig. 5, differs from the others also in this particular, that the exhaust takes place at the end of the valve instead of under the arch. Two eccentrics are used, the one for the main valve being fastened to the shaft and the other riding loosely upon it and connected to the fly wheel governor, by which it may be turned forward or back as the load requires. The three points of lead, or admission and exhaust and compression, are fixed and independent of the changes and cut off. The motion of the main eccentric is given to a rocker arm, the pivot of which is at the bottom, and from the upper end the valve rod transfers the motion to the valve without reversing the motion, as is done sometimes in the slide valve to overcome the effects of the angularity of the connecting rod. The action of the rocker arm, therefore, so far as the main valve in the Buckeye is concerned, is no different than that which would occur if no rocker arm intervened. The motion of the cut off eccentric, through its eccentric rod, is given to a rocker rocking in a bearing in the center of the main rocker arm (see Fig. 6). The motion of this eccentric is reversed, so far as the cut off valve is concerned, and when the cut off eccentric is moving forward, the cut off valve is being pushed back. The main valve rod is hollow, and the cut off valve rod passes through it. [Illustration: Fig. 6]