Where persons
reciprocally promise, firstly, to do certain things which are legal, and, secondly, under specified
circumstances, to do certain other things which are illegal, the first set of promises is a contract, but the
second is a void agreement.
Illustration
A and B agree that A shall sell B a house for 10,000 rupees, but that, if B uses it as a gambling house, he shall pay A 50,000
rupees for it.
The first set of reciprocal promises, namely, to sell the house and to pay 10,000 rupees for it, is a contract.
The second set is for an unlawful object, namely, that B may use the house as a gambling house, and is a void agreement.