This card sorter (from Gaylord) was used to sort catalog cards, first into smaller categories (like Dewey centuries or Library of Congress classes), and then those piles were sorted individually. In computer science, this is called a bucket sort. This particular card sorter has been modified to allow half-century buckets (e.g. 151-200 in one stack). We must have had a lot of cards to sort!
Petroleum, past, present & future / by Per K. Frolich. (OCLC #6283891)
Throwback Thursday! Let’s look at some catalog cards.
These two cards represent the same book, and are identical except for the heading at the top of the card: the top card is a title card (its heading is the book’s title) and the bottom card is a subject card (its heading is the LCSH subject heading for Petroleum. In this case they are so similar that the two cards were filed right next to each other in our card catalog, but normally they could be quite far apart; the author card, for example, would be in an F drawer near all the other Frolichs.
Subject cards can usually be distinguished from title cards by some decoration on their heading, such as being in all caps (like this example) or being printed in red ink.