Answer:
These lines are spoken by Casca.
The lines are about Brutus.
The lines mean that whatever bad plans that Cassius and Casca had planned can be turned to their advantage by Brutus in front of the people. Even though the people will get mad and angry after the death of Caesar, Brutus can turn them to their side, like an alchemist can turn anything into gold.
Explanation:
William Shakespeare's "The Tragedy of Julius Caesar" revolves around the story of how Julius Caesar was murdered by his trusted aides. Moreover, the future of Rome was left at the hands of numerous 'hopefuls' like Cassius and Brutus and Antony and Octavius on the other, fighting to get the power to rule over Rome.
The given lines are taken from Act I scene iii of the play, spoken by Casca. The lines refer to Brutus, who, according to Casca, is capable of turning the people's hatred into love, acceptable even if it is the worse of all things.
Cassius and Casca were planning to get rid of Caesar and wanted to rope in Brutus, which Cassius reveals <em>"Three parts of him Is ours already"</em>. And the things that they planned, however brutal it may be, can be turned around in the people's mindsets by Brutus alone. Like Casca states,
<em>"that which would appear offense in us,
</em>
<em>His countenance, like richest alchemy
</em>
<em>Will change to virtue and to worthiness".
</em>