The following are the recognised international symbols of the legal denominations of metric weights and €་ྔ=<དྗེ་༤ |Symbole. Poids. Symbole. dal Quintal métrique q kg Gramme cl ml Centigramme cg = 0.001 7. Milligramme mg Microgramme y 0.001 mg. = For instance, 100m means 100 metres; or 100m2 100 square metres; or 1000g = 1000 grams, &c. metric The Metric system had its origin in 1790, when an Original attempt was made by the French National Assembly standards. (Decree, 8th May 1790) to make the metric system compulsory in France, and to establish a decimal system based on the metre, or the one ten-millionth part of the quadrant of a meridian (see "Base du Système Métrique Décimal ou mesure de l'arc du méridien entre Dunkerque et Barcelone " par MM. Méchain et Delambre, Paris. 1810.); the gram weight then being declared to be equal to the weight of distilled water contained in a cubic centimetre (or a vessel whose linear dimensions were equal to one-hundredth part of the length of the metre). The original standards were made in 1795, 18 Germinal, An. III. (7th April, 1795), under the direction of the National Institute of Science, and in 1799, 19 Frimaire, An. VIII. (9th December, 1799), were deposited at the Palais des Archives at Paris. In the years 1801 and 1812 (Decrees, 3rd November 1800 and 12th February 1812), however, the French Governnient found it necessary to again permit the use in trade of the old French weights and measures (système-usuel) and it was not until 1840 (Law, 4th July 1837) that their use was finally forbidden. In other countries, however, the metric system has been made legally compulsory in less time-from two to ten years. Some of the old French denominations were similar to ours, as pinte or pint, tonneau or ton, boisseau or bushel, once or ounce, grain, mille, perch, &c. If the Standard Metre was lost or injured it would not now be restored by reference to the meridian, but by reference to existing material copies of the present metre prototype deposited with the various high contracting States who have joined the Metric Convention of 1871. The ideal metre (Clarke's "Geodesy," 1880), as determined by more recent geodetic measurements, is not equivalent to 39.37079 inches, but to 39-37779, as compared with Clarke's value of the metre, viz., 39.37042 inches, not a difference (0.007 inch) of much trade importance, perhaps, but one of importance for scientific and manufacturing purposes. The gram also would be restored by reference to the "kilogram-prototype" at Paris (1,000 grams), and not with reference to the weight of water. The capacity of the litre measure, similarly, would not depend on the weight of a cubic decimetre of water, but would be taken as equal to a kilogram weight of water. In hydrostatic weighings densities and volumes should be expressed therefore in litres or parts of a litre, and not in cubic centimetres; for instance, in a millilitre (ml.) or a gram weight of water at 4° C., and not in cubic centimetres. Denomi The actual weights and measures used in workshops nation of and factories are represented by the following series: metric weights. Iron and brass weights. 2 2 1 Double decalitre, or Decalitre Double litre Litre Demi-litre Double decilitre Decilitre Demi-decilitre Double centilitre Centilitre 5 4221 A glass litre measure, sub-divided into 1,000, 500, 200, 100, 50, 20, 10, 5, 2, 1 millilitres (ml.). Metre, sub-divided into 10 decimetres, the decimetre Measures of length being divided into 10 centimetres and the centimetre into made of 10 millimetres. Double metre, 20-metre, and 40-metre chains. brass, steel, wood, &c. Teaching of metric weights and It will be seen that in the above convenient series 5, 2, 2, 1, there is a duplicate weight of the 2, so as to obtain the multiple 10. A metric series is also in use abroad, based on weights of the proportions 5, 2, 1, 1; our decimal troy ounce series is 5, 4, 3, 2, 1; thus in the former series a third weight, 1, is needed to make up 10, making altogether five weights in place of the four used in the series 5, 2, 2, 1. In some grain weight series a convenient duodecimal series is also followed, as 12, 6, 3, 2, and 1. The facing diagrams (Figures 22, 23, and 24) show the shapes of the ordinary metric weights and measures. The proper way in which weights and measures may be taught in schools is shown in the Regulations of the Committee of the Privy Council on Education as hereafter in schools. referred to; but arithmetic books, unfortunately, often measures contain numerous local and customary weights and measures and obsolete terms of no practical use to a student. For instance, in a well known modern school book we are informed that cloth is measured by the "ell," a measure which legally and locally expired in this country half a century since, and a distinction is even drawn between the English and the obsolete Flemish ell. The student is further told that the hide is a measure of land although the hide was obsolete in 1701, and so on. Probably the only weights and measures that need be taught, are as follows: IMPERIAL SYSTEM. Weights. METRIC SYSTEM. 16 drams = 1 ounce (oz.) | 1 kilo-gram 1,000 grams. 16 ounces = = 8 stones = 1 hundred 1 pound (lb.) 14 pounds 1 stone. = 1 hecto-gram=100 1 deci-gram = 0·1 gram. |