Alexander von Humboldt, having published four volumes…

Alexander von Humboldt, having published four volumes of Kosmos, dies at the age of ninety in May of 1859.

The first volume is his attempt to describe the universe; the second summarizes humankind's efforts to reveal nature through landscape painting and exploration; the third covers astronomy; and the fourth deals with Earth and humans. (A fifth and final volume of Kosmos, based on Humboldt’s notes, will be published posthumously in 1862.)