"Four Temperaments"

[Mike and Jane Spalding]

List,

Looking through the latest catalog of music scores and books from Dover Publications, found this listing:
Symphony No. 2, Op. 16 "Four Temperaments" by Carl Nielsen.
Among the most popular symphonies of the twentieth century, this polytonal work by one of Denmark's leading composers is imbued with a special vigor and confidence.  In the symphony, according to Grove's Dictionary of Music and Musicians, Nielsen "did his best to help the ear by making the clash of opposed melodic strains clear by sharply differentiating their tone-colour."

Several questions come to mind:  Could Nielsen have been using the word "temperament" the same way we use the word?  If so, how does a composer record this intent in the score, and how would the conductor make it happen in the orchestra?  Anybody familiar with this work who can shed a little light?  

Inquiring minds etc. etc.

Mike