Mendeleev's predicted elements
Dmitri Mendeleev published a periodic table of the chemical elements in 1869 based on properties that appeared with some regularity as he laid out the elements from lightest to heaviest. When Mendeleev proposed his periodic table, he noted gaps in the table and predicted that as-then-unknown elements existed with properties appropriate to fill those gaps. He named them eka-boron, eka-aluminium and eka-silicon with atomic masses 44, 68 and 72 respectively.
Emerald Tablet
C.G. Jung identified "The Emerald Tablet" with a table made of green stone which he encountered in the first of a set of his dreams and visions beginning at the end of 1912, and climaxing in his writing "Seven Sermons to the Dead" in 1916. Historians of science, Eric John Holmyard (1891–1959) and Julius Ruska (1867–1949) also studied the tablet in the twentieth century. Because of its longstanding popularity, the "Emerald Tablet" is the only piece of non-Greek Hermetica to attract widespread attention in the West.