History of chemistry
An important breakthrough in making sense of the list of known chemical elements (as well as in understanding the internal structure of atoms) was Dmitri Mendeleev's development of the first modern periodic table, or the periodic classification of the elements. Mendeleev, a Russian chemist, felt that there was some type of order to the elements and he spent more than thirteen years of his life collecting data and assembling the concept, initially with the idea of resolving some of the disorder in the field for his students. Mendeleev found that, when all the known chemical elements were arranged in order of increasing atomic weight, the resulting table displayed a recurring pattern, or periodicity, of properties within groups of elements. Mendeleev's law allowed him to build up a systematic periodic table of all the 66 elements then known based on atomic mass, which he published in "Principles of Chemistry" in 1869. His first Periodic Table was compiled on the basis of arranging the elements in ascending order of atomic weight and grouping them by similarity of properties.
Rime table
The oldest known rhyme tables are a version of the "Yunjing" published with prefaces dated 1161 and 1203, and the "Qiyin lüe", which was included in the 1161 encyclopedia "Tongzhi". The two are very similar, and are believed to be derived from a single version pre-dating the Song dynasty. The tables were accompanied by a body of teachings known as "mēnfǎ" (), including rules for placing fanqie spellings that did not conform to the system within the tables.