Fluorinated gases pharmaceutical industries, as well as in refrigeration when combined with other gases. PFCs were commonly used as fire extinguishants in the past and are still found in older fire protection systems. They are also a by-product of the aluminium smelting process. Sulphur hexafluoride (SF) is used primarily as an insulation gas. It can be found in high-voltage switchgear and is used in the production of magnesium. HFCs were developed in the 1990s to substitute substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). As these substances were found to deplete the ozone layer, the Montreal Protocol lays down provisions for them
The Horse that Lost its Liberty (1484) under the title “Of the hors, of the hunter and of the hert” as teaching the moral given by Aristotle that "None ought to put hym self in subiection for to auenge hym on other". Samuel Croxall cites Horace’s conclusion that one should never yield one’s liberty to another for reasons of avarice. The fable was told as “The horse seeking vengeance on the stag ("Le cheval s'étant voulu venger du cerf") in La Fontaine's Fables and ends on the reflection that without personal liberty all other purchases are valueless: The alternative version of the fable concerns a boar