What are Cassius' feelings toward Caesar? What does he want of Brutus?

In Shakespeare's Julius Caesar,
Cassius is jealous and envious of Caesar.  He sees Caesar as just an ordinary man, like
himself.  He tells the story of a time when he rescued Caesar from drowning, which
demonstrates, in his own mind, anyway, that he is even Caesar's superior.  Yet, Caesar,
not Cassius, is praised by the Roman crowd and offered a crown by Antony.  Cassius, of
course, is also ambitious himself, and is interested in personal
gain.

Brutus is Caesar's loyal supporter and a preeminent
man of power in Rome.  He has both power and influence.  He is politically of higher
rank than Cassius.  Cassius needs his approval in order to go ahead with something as
grand as the assassination of Caesar.  Cassius needs Brutus's
support. 

Ironically, while Cassius needs support from
Brutus to go ahead with his plan, he'd have been much better off leading the conspiracy
himself, once the assassination was over.  Cassius makes sound decisions, while Brutus
causes the civil war and the eventual destruction of the conspirators.