Ozone layer an altitude of 100 kilometers from the planet's surface. The photochemical mechanisms that give rise to the ozone layer were discovered by the British physicist Sydney Chapman in 1930. Ozone in the Earth's stratosphere is created by ultraviolet light striking ordinary oxygen molecules containing two oxygen atoms (O), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O to create ozone, O. The ozone molecule is unstable (although, in the stratosphere, long-lived) and when ultraviolet light hits ozone it splits into a molecule of O and an individual atom of oxygen, a continuing process
The Layer Monument skull is the commonest of all "memento mori" symbols in funerary art. It was also defined as the philosophical vessel ("Vas Philosophorum") in Renaissance-era alchemy. The role of the Quaternity in religious symbolism is discussed in depth in the writings of the Swiss psychologist Carl Gustav Jung. In essence, the Layer monument's four figurines represent spiritual entities which agree with Jung's analytical psychology, that the psyche moves toward individuation in fours (made up of pairs of opposites). The Layer Monument The Layer monument is an early 17th-century polychrome marble mural monument (320 × 350 cm) erected to the memory of