"Though this be madness, yet there is method in't. Will you walk out of the air, my lord?"
This sentence has two independent clauses joined by a comma and the conjunction "yet". The first clause, "Though this be madness", is a subordinate clause that modifies the second clause, "Will you walk out of the air, my lord?". The sentence also contains a prepositional phrase, "out of the air", which modifies the verb "walk".