>...the concept must be an old one.

indeed, with many related shadings.

1602 Vpon the heate and flame of thy distemper Sprinkle coole patience. -Hamlet

1855 While she wept, and I strove to be cool. -Tennyson

1947 (record by Charlie Parker Quartet, Dial 1015) Cool Blues.

1959 Observer They got long, sloppy haircuts and wide knot ties and no-press suits with fat lapels. Very cool.

by the way, CK, don't confuse the hippies with the beats; it was the latter who are associated with cool jazz.

afterthought: Maynard G. Krebs was a beatnik, not a hippy!