MENSURATION OF SOLIDITY AND CAFACITY. General rule.- -Set the length upon в to the gaugepoint upon a; and against the side of the square, or diameter on D, are the cubic contents, or weight in lbs. on c. 1. Required the cubic contents of a tree 30 feet in length, and 10 inches quarter girt. Set 30 upon в to 144 (the gauge-point) upon A; and against 10 upon D is 20.75 feet upon c. 2. In a cylinder 9 inches in length, and 7 inches diameter, how many cubic inches? Set 9 upon в to 1273 (the gauge-point) upon a ; and against 7 on D is 346 inches on c. 3. What is the weight of a bar of cast iron 3 inches square, and 6 feet long? Set 6 upon в to 32 (the gauge-point) upon a ; and against 3 upon D is 168 lbs. upon c. By the common rule. 4. Required the weight of a cylinder of wrought iron 10 inches long, and 5 diameter. Set 10 upon в to 283 (G. Pt.) upon a; and against 5 upon D is 66.65 lbs. on c. 5. What is the weight of a dry rope 25 yards long, and 4 inches circumference? Set 25 upon в to 47 (G. Pt.) upon a; and against 4 on D is 53.16 lbs. on c. 6. What is the weight of a short-linked chain 30 yards in length, andths of an inch in diameter? Set 30 upon в to 52 (G. P.) upon ▲ ; and against 6 on D is 129.5 lbs. on c. LAND SURVEYING, If the dimensions taken are in chains, the gaugepoint is 1 or 10; if in perches, 160; and if in yards, 4840.-Rule. Set the length upon в to the gaugepoint on A; and against the breadth upon a is the content in acres upon B. 1. Required the number of acres or contents of a field 20 chains 50 links in length, and 4 chains 40 links in breadth. Set 20-5 on в to 1 on A; and against 4.4 on A is 9 acres on B. 2. In a piece of ground 440 yards long, and 44 broad, how many acres? Set 440 upon в to 4840 on A; and against 44 on a is 4 acres on B. POWER OF STEAM ENGINES. Condensing Engines.-Rule. Set 3.5 on c to 10 on D; then D is a line of diameters for cylinders, and c the corresponding number of horses' power; thus, H.Pt. 31 4 5 6 8 10 12 16 20 25 30 40 50 on c. C.D. 10 in. 10 12 13 15 17 18 24 26 29 33 37 on D. The same is effected on the common rule by setting 5 on c to 12 on D. 21 Non-condensing Engines.-Rule. Set the pressure of steam in lbs. per square inch on в to 4 upon A; and against the cylinder's diameter on D is the number of horses' power upon c. Required the power of an engine, when the cylinder is 20 inches diameter and steam 30 lbs. per square inch. Set 30 on в to 4 on A; and against 20 on D is 30 horses' power on c. The same is effected on the common rule by setting the force of the steam on в to 250 on A. OF ENGINE BOILERS. How many superficial feet are contained in a boiler 23 feet in length and 5 in width ? Set 1 upon в to 23 upon a; and against 5.5 upon в is 126.5 square feet upon a. If 5 square feet of boiler surface be sufficient for each horse-power, how many horses' power of engine is the boiler equal to ? Set 5 upon в to 126.5 upon A; and against 1 upon в is 25.5 upon A. |