3 inch cube full of air floats 1 lb. in water.
3 inch cube of water weighs 1 lb. in air.
1 cubic foot of water weighs 64 lb. in air.
1 ditto coal ditto 80 - 64 = 16 in water.
1 ditto sand ditto 95 - 64 = 31 in water.
A suit of clothes and a pair of boots, which weigh 7 lb. in air, when well saturated with water, only weigh in water 1 lb.
[55] Vide also Definitions—[Trigonometry], [page 301].
[56] Gunter’s chain is in length 4 poles = 22 yards = 66 feet, and is divided into 100 links. Each link is therefore 22 100 of a yard, or 66 100 of a foot, or 7·92 inches. Land is estimated in acres, roods, and perches. An acre contains 10 square chains, or as much as 10 chains in length and 1 chain in breadth; or in yards it is 220 × 22 = 4840; or in poles it is 40 × 4 = 160 square poles; or in links it is 1000 × 100 = 100,000 square links. An acre is divided into 4 parts called roods, and a rood into 40 parts called perches, which are square poles, or the square of a pole of 5½ yards long, or the square of a quarter of a chain, or of 25 links, which is 625 links. Thus the divisions of land measure are—
| 625 | square links | = 1 pole, or perch. |
| 40 | perches | = 1 rood. |
| 4 | roods | = 1 acre. |
The length of lines, measured with a chain, should be set down in links as integers, instead of in chains, and decimals. Therefore, after the content is found, it will be in square links.
[57] 57·3 is the number of pounds of powder contained in a cubic foot, when shaken; and 55 pounds when not shaken. According to the first case, one pound of powder will occupy 30 cubic inches; and according to the second case one pound will occupy 31·4182 cubic inches.
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