METRIC SYSTEM. 394 METRIC SYSTEM. Hektare Acre Kilo- EnpT. 1 .Square Kilo- Enir. meter miles meter miles 0.405 1 2.471 1.609 1 0.621 2.592 1 0.386 0.809 3 4.942 3.219 2 1.243 5.184 2 0.772 1.2U 3 7.413 4.828 3 1.864
- 7.776
3 1.158 1.619 4. 9.8S5 6.438 4. 2.486 10.368 4, 1.644 2.023 5 12.356 8.1M7 5 3.107; 12.960 e 1.930 2.428 6 14.227 9.656 e 3.728|| 15. .532 6 2.316 2.833 T 17.898 11.265 7 4.350 18.144 7 2.702 S.237 8 19.769 12.879 8 4.9Tl!i 20.736 8 3.088 3.M'2 9 22.240 14.484 9 5.592 ' 23.328 9 3.474 4.1W7 lO 24.711 16.093 lO 6.214 1 25.920 10 3.860 B.lWi 30 49.423 32.1S6 20 12.428 61.840 20 7.720 12.140 30 74.1:)4 48.279 30 IS. (HI 77.760 SO 11.580 1G.1K7 4.0 a«.K46 64.373 ■to 24.855 10:1. BSO 4.0 15.440 20.1>34 SO 123.557 80.466 SO 31.(I69 129.60(J SO 19.300 24.2.S6 60 148.26,S 96.659 60 37.283 l.'i5.520 60 23.160 28. 327 70 172.980 112.0.W 70 43.497 1HU440 70 27.020 32.373 SO 197.692 lis. 746 SO 49.710 207.3(ai SO 30.8NO 36.421) 90 222.903 144.839 90 .55.924 233.280 90 34.740 40.467 ICO 247.114 160.932 lOO 62.138 259.200 100 38.601 Tlic advantages of the metric system over the English-.Vmerican sj-stem are numerous. Al- though, in both sy.sfems, the .standard units of volume, capacity, and weight are directly con- nected with the standard unit of measure, the relation in tlic l<"ren< h system is far more simple. Thus, in the English system one quart has a volume of 57 % cubic inches, while in the French system one liter has the volume of one cubic decimeter; in the English system the pound has the weight of about 0.0150 of a cubic foot of standardized water, while in the French system one gram has the weight of one cubic centimeter. Although the names used in the metric system are generally longer than the names used in the English-.Vmerican system, the nomenclature of the former has several advantages. Thus, the prefixes deci, centi, niilli, deka, liekto. kilo have in i)oint of derivation a numerical significance and have other applications in the language. while the names inch, foot, yard, rod, and mile are devoid of numerical significance and are dis- tinctive in their u.se. But the greatest advantage of all results from the use of a uniform scale of relation. In the English-.merican system seldom do more than two units in succession have the same scale. Thus, in the metric system, 10 centimeters = 1 decimeter. 10 decimeters = 1 meter, . . . , the ratio being always 10; while in the English system. 12 inches = 1 foot, 3 feet = 1 yard, 5i/> yards = 1 rod, . . . , the ratio changing between every i>air of units. The French Commission of 17110 reported in favor of the decimal scale for reasons of expediency, althniigh admitting that the uniform scale of 12 possessed many advantages. The metric system was once thought to be su[HTior to all other systems of weights and measures in being founded on an invariable magnitude, one ten-millionth of ,a terrestrial quadrant. But science has dispelled this illusion by showing that this magmilude is not a constant nnd that the distance originally taken as the basis of the meter was inaifurately measured. In 1840 the French Government comelved the idea of exchanging sets of the metric units for sets of the units of other nations in order to promote an international interest in the metric system. The international expositions at Lon- don (1851) and at Paris (1855) were, on account of the immense variety and confusion of metrical imits. the first practical demonstrations of the need of a tiniversal decimal system of weight.s and measures. At the Paris Exposition of 1867 a committee, representing several dilTorent na- tions, was appointed to consider the question of uniformity, and was called the Committee of Weights, -Measures, and Jloneys. Slalhieu was the president of this commission. The com- mittee recommended instruction in the metric system in the public schools and its use in Gov- ernmental departments and in scientific publica- tions. The Ceodetic Association, which met at Berlin about this time, was also repnsrnlative of several nations, and likewise favored the gen- eral adoption of the metric system. In the year 1809 a committee of the Academy of Sciences at Paris and one of the Saint Petersburg .-Vcadeniy recommended the convocation of an international commission, which should consider the means of providing all nations with sets of standard metric units. Such a commission was invited liy the French Government, and as,sembled at Paiis in 1870. Twenty- four countries responded by send- ing delegates. Joseph Henry and .Julius E. Hil- gard representing the United States. This body was divided into committees, the most permanent one being the French swtion, for the purpose of devising means for copying the standards pr. served in the archives. Some of the question> which concerned the committee were the com- position of the metal to be used in constructing the new unit of length, the most desirabU- form of cross-section, ways of expressing the h'ngth, as the distiince between the ends, or between two fine lines made on the bar, means of comparing the new unit with the standard of the -Vrchivca, means for determining its variation due to changes in temperature, and other consideration.s. The French section met in 1872 and |)ropose(l that an international bureau of weights and measures be located at Paris, the original con- ception of the International Bureau being later decided upon at the diplomatic conference of 1875. At the second meeting of the Inter- national Commission in 1872 it was decided to make the standard meter and the stand' ard kilogram of the .rchivcs the actual bases for the new standards. In order to give the work of the ccmimission the character of an international act. its members so far Iwing simi)ly citizens of their respective countries, the French Government invited plenipotentiaries and delegates from all of the nations interested. Rep- resentatives from twenty States assembled at Paris (1875) to constitute the Diidomatic Con- ference of the Meter. E. B. Washburne acted as plenipotentiary and II. Vignaiid as delegate for the Lniled States. The Observatory of the International Bureau, decided ujion by this con- ference, was comjileted in 1878. It stands at the entrance of the park of .'>aint Cloud on a reserva- tion presented by the French Government. The management of the Bureau reposes in the Inter- national Committee under the authority of the (ieiieral Conference. In the Observatory are kept the instruments Used in the determination of the international standards, the chief of which are the comparators, balances, and thermometers. The extent of the demands upon this bureau may be inferred from the fact tliat in 1882 twenty- three countries requested twenty-nine meters and thirty kilograms; in 1880 they requested thirty- six meters and thirty kilograms. The mctetB are highly polished metal bars made of an alloy of platinum and iridium, ami the kilograms aW cylinders of the same material.
