Ozone layer upper-atmosphere ozone-depletion rate slowed down significantly during the previous decade. Some breakdown can be expected to continue because of ODSs used by nations which have not banned them, and because of gases which are already in the stratosphere. Some ODSs, including CFCs, have very long atmospheric lifetimes, ranging from 50 to over 100 years. It has been estimated that the ozone layer will recover to 1980 levels near the middle of the 21st century. A gradual trend toward "healing" was reported in 2016. Compounds containing C–H bonds (such as hydrochlorofluorocarbons, or HCFCs) have been designed to replace CFCs in certain
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