why does Calpurnia try to convince caesar of ?

Calpurnia dreams about Caesar's statue as a fountain pouring blood from hhundred's sprouts, and lusty Romans smiling and bathing their hands in the blood. 

Calpurnia tries to convince Caesar about her nightmares and paraphrases an age old belief that when an important person dies even the heavens mourn on the death. She pleas with him asking him not to go to the Senate and remain in the house.