Clock Vault of Ladd Observatory
The masonry pier that supports the Ladd Observatory's main telescope contains two clock vaults. The purpose of a clock vault is to provide a vibration-free and temperature-stable environment for precision timekeeping. The basement level vault is currently unused. The floor plan illustrates the main clock vault located in the entrance foyer on the first floor of the Observatory.
1. Entrance foyer
2. Brick wall (2 feet thick)
3. Vault (floor is a single granite slab)
4. Double door entrance
5. Clemens Riefler clock
6. Edward Howard clock
7. Robert Molyneux clock
The double doors to the vault have windows through which the Riefler clock can be observed without disturbing the environment inside. There are also telegraph wires to send time signals from the clocks to other parts of the building. Starting Sept. 12th, 1893 and continuing until as late as 1973 the Observatory also transmitted time signals to other locations including Providence fire stations.