The Whittemore Collection  
Box of special leads used to put marks on Mark Sensing Cards.  The mark completed an electrical circuit when read in an IBM 519 and it punched a hole in a corresponding location on the card. This was how A&P stores ordered their items from the warehouse. I used to run the 519.

Box of special leads used to put marks on Mark Sensing Cards. The mark completed an electrical circuit when read in an IBM 519 and it punched a hole in a corresponding location on the card. This was how A&P stores ordered their items from the warehouse. I used to run the 519.