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The first steps of humanity have already presented the need of finding units of metrology jobs training tools lab handbook services solutions companies classes measurement. The metres and weights were among the first discoveries made by human. Human body itself constituted the basis for the creation of the first metrical systems. Thus some of the first units been created was the daktylos, palami, vrahiwn, poys, step, etc. In cases of measurement of distances of big scale, the units were constituted by the distance of stone shot, the distance that covers in one day one pedestrian, the period of the sun, of the moon etc. Depending on the circumstances similar units is still used. . Despite the common root of most of metrical systems, these systems differed from place to place. Thus we had the parallel growth of many systems that rendered the transactions among populations difficult, however the small number of them had not created the need for finding of a world wide commonly acceptable metrical system. . In 1670 gabriel mouton being aware of the fact that this new metrical system should be based on earthly measurement, proposed a decimal metrical system, which would be based on the length of a thin arc of meridian while in 1671 jean picard, a french astronomer, proposed one unit of length based in pendulum. Nevertheless one century had to pass up to the creation of metric system. . In 1790 in the means of french revolution, the french national assembly assigned to french academy of sciences to create immutable models for all the meters and all the weights. The academy created a system of units that was simultaneously simple and scientific based on the proposal of mouton. . Finally as unit of length as well as basis of metric system was defined a meter, which counterbalances with one-tenth millionth quadrant of length of meridian that it goes through from paris. The multiples and submultiples of the new units resulted from multiplying and dividing respectively the basic units with the 10, something that made the new system of units more functional. The new units of surface and volume resulted from the meter and were the square and cubic meter respectively. Also as a basic unit of weight was determined the gram, which is equal to the mass of a cubic centimeter of clean water in the temperature of biggest density (4 c). The liter resulted from the volume of cube with length of each side equal with 10 centimeters. . Even thought the metric system was not accepted with enthusiasm, its adoption from other nations began to increase regularly after its obligatory use in france 1840. It is not accidental that the growth of metrical system coincided with the technological growth in europe and america. . In the end of 1860 became obvious the need for existence of more precise and explicitly determined units, because of the requirements being created by the new scientific discoveries. This became possible with the treaty of meter (meter convention) in 1875, an international treaty in which participated 17 countries among which was also the usa, while up to 1900, 35 nations had officially accepted the metric system. . The duty of the international office of meters and weights of sevres in france is the permanent secretariat of the treaty of meter as well as the exchange of information referring to the use and the improvement of metrical system. The office extended the work of international standardization in electric models (1921), in the models of lighting (1933) and in the models of measurement of jonjzoyswn radiation (1960). The same year (1960) a generalized simplification of metric system as well as his denomination in to international system of units (systeme international d& ,unites - s. I. ) was decided. . In 1964, 1967-1968, 1971, 1975, 1979, 1983, as well as the 1991 further improvements in the s. I became. The international system of units has been established worldwide following simultaneously the continuously created scientific needs for the determination of new and more precise metrical units. . .
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