What's the difference between fugacious and fugaciousness?

Fugacious

Definition:

• (a.) Flying, or disposed to fly; fleeing away; lasting but a short time; volatile.
• (a.) Fleeting; lasting but a short time; -- applied particularly to organs or parts which are short-lived as compared with the life of the individual.

Example Sentences:

• (1) Facebook Twitter Pinterest The Reporter, on the other hand, calls it "a fugacious bit of whimsy that can only be judged minor Woody Allen".
• (2) However, it may be revealed inconstantly and fugaciously by ultasonic lysis of cells infected by sera containing Dane particles.

Fugaciousness

Definition:

• (n.) Fugacity.

Example Sentences:

• (1) Facebook Twitter Pinterest The Reporter, on the other hand, calls it "a fugacious bit of whimsy that can only be judged minor Woody Allen".
• (2) However, it may be revealed inconstantly and fugaciously by ultasonic lysis of cells infected by sera containing Dane particles.