METRIC SYSTEM OF WEIGHTS AND MEASURES. 577. The Metric System of weights and measures is used by most of the civilized nations of the world except the United States and Great Britain and some of her colonies. It has also been legalized by the United States government. 578. The unit of length is the meter, and from it the other units, viz.: surface, volume, capacity, and weight are derived. 1. The length of the meter was intended to be one ten-millionth of the distance from the equator to the poles, but subsequent calculations have shown it to be a very little less than that. 2. The system derives its name from the meter, because all the units of measure in the system are derived from it. 3. The system has a decimal notation. 579. From the standard units other denominations are formed by the use of prefixes derived from the Latin and the Greek. Deci means 10th. Centi means 100th. Milli means 1000th. Deka means 10. Kilo means 1000. Thus, decimeter, of a meter; dekameter, 10 meters. 580. The following tables give all the denominations, but many of them are not in common use. Those usually employed in business or science are indicated by bold-faced type. Abbreviations beginning with a small letter indicate a fractional part of the standard unit; those beginning with a capital denote a multiple of the unit. 582. The units of surface are squares whose dimensions are the corresponding linear units; hence it requires 10 times 10, or 100, of a given denomination to make one of the next higher. TABLE. 100 Sq. Millimeters = 1 Sq. Centimeter =.155+ sq. in. 100 Sq. Centimeters = 1 Sq. Decimeter = = 15.5+ sq. in. = 1.196+ sq. yd. = 247.114 A.=.3861 sq. mi. = 1. In measuring small areas the unit is the sq. meter. 2. In measuring land, the square meter is called a centare (ca), the square dekameter an are (a) and the square hektometer a hektare (Ha). MEASURES OF VOLUME. 583. The units of volume are cubes whose dimensions are the corresponding linear units; hence it requires 1000 of a given denomination to make one of the next higher. MEASURES OF CAPACITY AND WEIGHT. 413 TABLE. 1000 Cu. Millimeters (cu mm) = 1 Cu. Centimeter (cu cm). 1000 Cu. Centimeters 1000 Cu. Decimeters = 1 Cu. Decimeter (cu dm). = 1 Cu. Meter (cu m). 1. In measuring volumes the principal unit is the cubic meter. 2. In measuring wood, the cubic meter is called a stere, † of a cubic meter a decistere, etc. 3. A cubic meter is equal to 1.308 cubic yards. MEASURES OF CAPACITY. 584. The unit of capacity in both liquid and dry measure is the liter, and it contains a volume equal to a cube whose edge is a decimeter. 585. The unit of weight is the gram, and its weight is the weight of a cubic centimeter of distilled water at its greatest density. REDUCTION. 586. A denominate number in the metric system can be reduced to higher or lower denominations by the removal of the decimal point. 1. In measures of volume, since it requires 1000 of each denomination to make one of the next higher, the decimal point must be removed three places. 2. In measures of surfaces, since it requires 100 of each denomination to make one of the next higher, the decimal point must be removed two places. 3. In other measures remove the decimal point one place. EXERCISES. 587. 1. Reduce 15675cm to kilometers. 2. Reduce 7560sq m to ares. 3. Write 6734 as liters; as hektoliters. 6. Write 876.378q cm as square meters; as ares. 8. What is the weight in dekagrams of .045eum of water? 9. What is the weight in kilograms of 13 of water? 10. How much will a cubic meter of water weigh in kilograms? Express the same quantity of water in liters. 11. What is the amount of 65750.75' of water in cubic meters? What is its weight in kilograms? A milliliter of water weighs 1 gram. 12. What will 601 of mercury weigh, mercury being 13.5 times as heavy as water? The weight of any substance compared with the weight of an equal bulk of water is called its specific gravity. The sp. gr. of mercury is 13.5. 13. Find the weight in grams of a cubic decimeter of iron (sp. gr. 7.21). 14. What is the weight in kilograms of a cubic meter of ice (sp. gr. 0.92)? 15. Which is the cheaper and how much, to buy cloth at $3 per meter, or at $2.90 per yard? 16. How many ares are there in a rectangular field 62m long and 43.6m wide? 17. Find in square meters the area of the floor of a room 5.3 meters long and 4.2 meters wide. 18. How many liters of water are there in a tank 2.6m long, 2m wide, and 6am deep? 19. How long must a pile of wood be, to contain 12 steres, if it is 3.5 meters high and 3.8 meters wide? 20. A barrel of flour contains 196 pounds. How many kilograms or kilos does it weigh? 21. A bin is 3 meters square and 2.5 meters high. How many hektoliters of wheat will it hold? 22. What weight of mercury will a vessel contain whose capacity is 25eu em ? 23. A tank is 4m long, 36dm wide, 76cm deep. How many liters of water will it hold? 24. A vat is 6.4m long, 3m wide, and 2.8m deep. How long will it take a water-pipe to fill the vat, if 2.9D flow into it per minute? 25. A platform bears a weight of 60 pounds per square foot. What is the weight in kilograms per square meter? 26. A man bought 360 bu. of wheat at $.95 a bushel, and sold it at $2.95 a hektoliter. How much did he gain? 27. The dimensions of a box are 3.5m, 1.8m, and 0.8m. What are the contents in cubic yards? 28. A room is 5.2 meters long, 4.5 meters wide, and 3.2 meters high. What will be the cost of plastering it at 35 cents per square meter? |