It is said that a usage must be general; that one instance does not make a usage.1 This means that a usage must be uniform and certain, and uniformly acted upon.2. But it may very well be that the usage may be that of all the banks at one place or a particular bank at a place.3 But even if the usage is a general one among banks, if a particular bank has abandoned it the usage is non-existent as to that bank.4 Nor will the usage of any number of banks control a bank which has not adopted it.5 A person dealing with a particular bank is said to be presumed to know the usage of that particular bank,6 and it has been held that the bank may abrogate its usage without notice to its customer;7 but this decision cannot be correct because the customer is held to know the usage, and after he has found it out, by some species of omniscience, he is required to know that the bank has abrogated it. The contrary rule is correct.8