Very high and very low temperature extinguishes all human sympathy and relations. It is impossible to feel affection beyond 78° or below 20° of Fahrenheit; human nature is too solid or too liquid beyond these limits. Man only lives to shiver or to perspire. God send that the glass may fall, and restore me to my regard for you, which in the temperate zone is invariable.

— Sydney Smith, letter to Sarah Austin, July 1836