Mirth is short and transient, cheerfulness fixed and permanent† Mirth is like a flash of lightning that breaks through a gloom of clouds, and glitters for a moment: cheerfulness keeps up a kind of day-light in the mind, and fills it with a steady and perpetual serenity.

-Addison,Joseph
  In The Spectator, no.381,17 May.

Our doom is, to be sifted by the wind, heaped up, smoothed down like silly sands. We are less permanent than thought.

-Bunting, Basil
  Villon, pt.1.

The word permanent†had its own kind of revenge on those who misused it, for the Bible said that nothing was permanent and everything came and went.

-Frame,Janet Paterson also known as Jean PatersonFrame
  To the Is-land, ch.2,'Toward the Is-Land'.

But liberty, as we all know, cannot flourish in a country that is permanently on a war footing, or even a near-war footing. Permanent crisis justifies permanent control of everybody and everything by the agencies of central government.

-Huxley, Aldous Leonard
  'Brave New World Revisited', in Esquire.

Iamnot yet so lost inlexicographyastoforgetthat words arethe daughters of earth, and thatthings arethesons of heaven. Language is only the instrument of science, and words are but thesigns of ideas: Iwish, however, that the instrument might be less apt to decay, and that signs might be permanent, like the things which they denote.

-Johnson, Samuel known as Dr Johnson
  A Dictionary of the English Language, preface.

Das, worin man die nationalen Unterschiede findet, ist viel mehr, als man bis jetzt eingesehen hat, nur der Unterschied verschiedener Kulturstufen und zum geringstenTeile etwas Bleibendes (und auch dies nicht in einem strengen Sinne). National differences consist, far more than has hitherto been observed, only in the differences of variousgrades of culture, and are only to a very small extent permanent (and not even that in a strict sense).

-Nietzsche, FriedrichWilhelm
Nachgelassene Fragmente.