Case Carlill v Carbolic Smoke Ball Co 
Facts An advert placed for 'smoke balls' to prevent influenza. offered to pay £100 if anyone contracted influenza after using the ball. Deposited £1,000 with the Alliance Bank to show their sincerity in the matter. The plaintiff bought one of the balls but contracted influenza
Held she was entitled to recover as (a) The deposit of money showed an intention to be bound, therefore the advert was an offer; (b) It was possible to make an offer to the world at large, which is accepted by anyone who buys a smoke-ball; (c) The offer of protection would cover the period of use; and (d) The buying and using of the smoke-ball amounted to acceptance. The court dismissed the case. There cannot be assent without knowledge of the offer; and ignorance of the offer is the same thing whether it is due to never hearing of it or
Acceptance of R v Clarke The Government offered a offer has to be reward for information  communicated. leading to the arrest of certain murderers and a pardon to an accomplice who gave the
information. Clarke saw the forgetting it after hearing." proclamation. He gave information which led to the conviction of the murderers. He admitted that his only object in doing so was to clear himself of a charge of murder and that he had no intention of claiming the reward at that time. He sued the Crown for the reward Revocation has to be communicated. Byrne V An offer made on 1st October Leon Van (In Cardiff). Claimant (in  New York) received it on 11th & send acceptance at once. In the main time the defendant change his mind and sent a letter of revocation on 8th Oct. Revocation letter The revocation was not complete until it had been communicated to the offeree. This was on 15th October. In the main time, however the offer had been accepted. As a result the revocation was ineffective & the contract did exist. The defendant was therefore liable under the contract.
reached on 15th Oct. Revocation can Dickinson Dodds offered to sell his be v Dodds house to Dickinson, the offer communicated being open until 9am Friday.  by a reliable On Thursday, Dodds sold the source. house to Allan. Dickinson was told of the sale by Berry, the estate agent, and he delivered an acceptance before 9am Friday. Offer does not Errington A father bought a house on laps with death mortgage for his son and v of offeree and Errington daughter-in-law and promised remains valid if them that if they paid off the  consideration is mortgage, they could have the being made. house. They began to do this but before they had finished paying, the father died. His As the Claimant knew that the defendant was no longer in a position to sell the property to him the defendant had drawn his offer validly. It was impossible, therefore, to say there was ever that existence of the same mind between the two parties which is essential in point of law to the making of an agreement. The father's promise was a unilateral contract - a promise of the house in return for their act of paying the installments. It could not be revoked by him once the couple entered on performance of the act. The couple was entitled to continue paying the installments and claim the house
widow claimed the house.
when the mortgage has been fully paid off.
A counter offer revokes the original offer.
Hyde v Wrench 
.6 June W offered to sell his estate to H for £1000; H offered £950 27 June W rejected H's offer 29 June H offered £1000. W refused to sell and H sued for breach of contract
Held that if the defendant's offer to sell for £1,000 had been unconditionally accepted, there would have been a binding contract; instead the plaintiff made an offer of his own of £950, and thereby rejected the offer previously made by the defendant. It was not afterwards competent for the plaintiff to revive the proposal of the...