4. On November 1st, Perkins installed a burglar alarm system in Moore's store. Moore signed a negotiable promissory note due on December 1 payable to the order of Perkins for $1100- the purchase price. On November 8 Perkins returned to Moore's store and told Moore that he needed money and would accept $1000 as payment in full. Moore paid Perkins the $1000, but forgot to obtain the note from Perkins. On November 10, after receiving his inventory bill from the Harris Burglary Alarm Factory and not having any additional ready cash, Perkins indorsed the 'Moore' note in blank and transferred it to Harris for value. Two days later, Harris learned that Moore had already paid Perkins for the note, whereupon he gave the note to Valerie, as a present, without further indorsement. Valerie was not aware of Moore's prior payment of the note. Valerie goes to Moore's store and demands her $1100. Discuss.