CAPACITY OF CISTERNS.

The following table gives the capacity of cisterns for each twelve inches in depth:

Diameter. Gallons.
25feet 3671
20„ 2349
15 „ 1321
14 „ 1150
13„ 992
12„ 846
11„ 710
10„ 587
9„ 475
8„ 376
7„ 287
61⁄2„ 247
6„ 211
5„ 147
41⁄2„ 119
4„ 94
3„ 53
21⁄2„ 36
2„ 23

Supposing it was required to find the weight of the water in any cistern or tank; it can be ascertained by multiplying the number of gallons by the weight of one gallon, which is 81⁄3 pounds, 8.333. For instance, taking the largest cistern in the above table containing 3671 gallons: 3671 × 8.33 = 30579.43 pounds.

The table above gives the capacities of round cisterns or tanks. If the cistern is rectangular the number of gallons and weight of water are found by multiplying the dimensions of the cistern to get the cubical contents. For instance, for a cistern or tank 96 inches long, 72 inches wide, and 48 inches deep, the formula would be: 96 × 72 × 48 = 331,776 cubic inches.

As a gallon contains 231 cubic inches; 331,776 divided by 231 gives l,436 gallons, which multiplied by 8.33 will give the weight of water in the cistern.

For round cisterns or tanks, the rule is: Area of bottom on inside multiplied by the height, equals cubical capacity. For instance, taking the last tank or cistern in the table: Area of 24 inches (diameter) is 452.39, which multiplied by 12 inches (height) gives 5427.6 cubic inches, and this divided by 231 cubic inches in a gallon gives 23 gallons.

Supposing the tank to be 24 inches deep instead of 12 inches, the result would be, of course, twice the number of gallons.

Rule for Obtaining Contents of a Barrel in Gallons.

Take diameter at bung, then square it, double it, then add square of head diameter; multiply this sum by length of cask, and that product by .2618 which will give volume in cubic inches; this, divided by 231, will give result in gallons.