The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public domain. I therefore think the slide rule itself is in the public domain under U.S. law. I'm making this diagram available under GFDL license.
2005-04-30 04:47 Bcrowell 456×40× (4493 bytes) This was made by manipulating a scan of a Pickett pocket slide rule, done by me, Benjamin Crowell, in 2005. The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public dom
2005-04-30 04:36 Bcrowell 456×40× (10473 bytes) This was made by manipulating a scan of a Pickett pocket slide rule, done by me, Benjamin Crowell, in 2005. The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public dom