The sloping face of the dam receives the direct pressure of the water and transfers it to the sills, which in turn transfer it to the concrete foundation. The reason for sloping the upstream face of the dam is that the pressure of water is always normal, or perpendicular, to the surface against which it presses; therefore, if the face of the dam is sloping, the pressure is downward, rather than outward, as would be the case with a vertical face. This results in greater stability for the dam, due to the lessened tendency to tip over. With a dam of this type the higher the water rises against or over it, the more nearly vertical is the line of pressure, and the dam is held tightly down on its foundation instead of tending to tip over. It follows that the flatter the face of the dam the more stable it will be. Mr. Miner’s dam raised the water about four feet. But in spite of his provision for floods, Mr. Miner did not want to be under the necessity of letting down his dam for every freshet, so he provided an additional permanent spillway. This is a simple concrete barrier, or wall, which flanks one end of the dam. In plan it was built at an angle with the dam proper, and extends downstream along the side of the natural bank. It was built with its crest a few inches higher than the main dam, so that during periods of ordinary flow the surplus water all passes over the main dam, but as soon as the creek rises a few inches over the main dam, water begins to flow over this extra spillway, which, being about forty feet long, will discharge a considerable volume although the water flowing over it is only a few inches in depth. This spillway is strengthened on the downstream end by a concrete abutment, which consists of a simple heavy block of concrete extending above the top of the spillway. A similar abutment flanks the upstream end and also constitutes an abutment for one end of the main dam. The other end of the main dam is set against the opposite bank of the creek and is protected from washing and is strengthened by a similar concrete abutment.