The metric system was first implemented during the French Revolution (1790s) with just the metre and kilogram as standards. In the 1860s British scientists, working through the British Association for the Advancement of Science laid the foundations for a coherent system based on length, mass and time, but the inclusion of electrical units into the system was hampered until 1900 when Giorgi identified the need to define an electrical quantity alongside the original three quantities. Meanwhile, in 1875, the Treaty of the Metre passed custodianship of the prototype kilogram and metre from French to international control. In 1921 the Treaty was extended to include all physics measurements and in 1948 an overhaul of the metric system was set in motion which resulted in the publication of the International System of Units in 1960.