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.
Iguvine Tablets
The Iguvine Tablets, also known as the Eugubian Tablets or Eugubine Tables, are a series of seven bronze tablets from ancient Iguvium (modern Gubbio), Italy. The earliest tablets, written in the native Umbrian alphabet, were probably produced in the 3rd century BC, and the latest, written in the Latin alphabet, from the 1st century BC. The tablets contain religious inscriptions that memorialize the acts and rites of the Atiedian Brethren, a group of 12 priests of Jupiter with important municipal functions at Iguvium. The religious structure present in the tablets resembles that of the early stage of Roman religion, reflecting the Roman archaic triad and the group of gods more strictly related to Jupiter. Discovered in a farmer's field in the year 1444, they are currently housed in the Civic Museum of the Palazzo dei Consoli in Gubbio.