A gallon of water occupies 277'27cub. in., and the capacity of the frustum of a cone can be obtained by adding to the sum of the areas of the two ends the square root of their product and then multiplying by one-third the vertical height.

The contents will be in cubic inches if the areas and heights are measured in square inches and inches respectively. Of course, there are many varieties of tapering vessels that will hold 1 gal., but, assuming that the diameters are 3 5/8 in. and 4 1/4. in. at bottom and top of the vessel respectively, the height can be determined as follows: - The areas of the two ends will be 3 5/8 x 3 5/8 x '7854 = 10.3 sq. in., and 4 1/4 x 41/4 x.7851 = 14.2sq. in. respectively; the product of these is about 144, its square root being twelve. The sum of the ends, etc., is therefore 10.3 + 14.2 + 12=36.5, so that the height should be 3 x277.27/36.5 = 22.7in. (say).