Posted 6 years ago
Available some time around 1917, this is a device that is used to determine the number of days from one date to another or to determine the date from a specified number of days from the chosen date. It is mechanical and consists of a main cylinder encased in a metal shell with a smaller dual counter mounted on the outside. It is meant for desk top use and measures in at 9.75"L x 6.75"W x 4.75"H.
A more in-depth write-up about this item can be found at https://americanstationer.wordpress.com/2013/05/12/the-national-time-computer/ .