Water supply for fountains etc

2256. With respect to strength, the pressure of water is as its depth, and consequently a dam, whose section is a right-angled triangle, and whose hypothenuse forms an angle of 45ﾦ, with the base formed of any material of greater specific gravity than water, would, as far as strength is concerned, hold in equilibrium a body of still water of a depth equal to its perpendicular. If the hypothenuse, or sloping side, be placed next the water, it will more than hold the water in equilibrium, by the weight of the triangle of the water superincumbent on the triangle of the dam or bank.