Julius Lothar Meyer
In 1869, Dmitri Mendeleev published a periodic table of all known elements (he predicted several new elements to complete the table, and corrected some atomic weights). A few months later, Meyer published a revised and expanded version of his 1864 table independently, which was similar to that published by Mendeleev (Meyer had been sent a copy of Mendeleev's table earlier; Mendeleev had sent it to many well-known chemists of his day) and a paper showing graphically the periodicity of the elements as a function of atomic weight. Meyer, as well as other chemists, was doubtful about Mendeleev's periodic law, and he criticized Mendeleev for "changing existing elements' atomic weights, only regarding possibility of periodical law in its structure". However, Mendeleev's work received significant support, when the new elements were found as predicted and atomic weights accordingly.
Multiplication table
The oldest known multiplication tables were used by the Babylonians about 4000 years ago. However, they used a base of 60. The oldest known tables using a base of 10 are the Chinese decimal multiplication table on bamboo strips dating to about 305 BC, during China's Warring States period.
The multiplication table is sometimes attributed to the ancient Greek mathematician Pythagoras (570–495 BC). It is also called the Table of Pythagoras in many languages (for example French, Italian and Russian), sometimes in English. The Greco-Roman mathematician Nichomachus (60–120 AD), a follower of Neopythagoreanism, included a multiplication table in his "Introduction to Arithmetic", whereas the oldest surviving Greek multiplication table is on a wax tablet dated to the 1st century AD and currently housed in the British Museum.