As you know among seven main SI
units the most vulnerable is kilogram
since itís a physical object made by humans
and it can be destroyed or damaged.
The definitions of ampere, mole,
and candela depend on the kilogram
definition. Over the past hundred years
of comparisons the stability of the kilogram
prototype nominal value in comparison
to the national standards demonstrated
their masses discrepancy by
50 μg. How this problem has been
solved you will learn from the present
135 years has passed from the day of signing of the Metrical Convention on the 20th of May, now the day is known as the World Metrology Day. On October 12 International Organization of Legal Metrology will celebrate its 55th anniversary. It means that in five years these two organizations can together celebrate the 200 anniversary of their metrological activity. This article tells about the history of their relations and a tendency to unite these organizations.†
In 2009 the International arrangement of mutual recognition of national standards and certificates of calibration and measurements, issued by national metrological institution celebrates its 10th anniversary which will take place in Paris, France. The article is devoted to this event and includes detailed history of the metrology which took several steps. The International arrangement, signed in 1999 in Paris, played a vital role for further development of metrology, for the creation of global measuring system which provides the unity of measurements in the whole world.
The article is devoted to 175th anniversary of Great Russian scientist D.I. Mendeleev, the author of fundamental research in chemistry, physics, metrology, aerostatics, economy and other sciences without which it would be difficult to imagine any achievement in the field of technical progress. The author tells about the work of D.I. Mendeleev in International Committee Measures and Weights