Washington Monument

The Washington Monument was built between 1848 and 1884 as a memorial to George Washington, first President of the United States.  The construction took place in two major phases, 1848 to 1856, and 1876 thru 1884. The Civil War and a lack of funds caused the delays.  In an elaborate Fourth of July ceremony in 1848, the cornerstone was laid. 

The Washington monument is composed of white marble from Maryland and Massachusetts,  supported by interior ironwork. A slight color change can be seen at the 152 foot level.  The color change is a result of the delays in the final construction.  During the twenty year period when the monument was not under construction, quarrying continued at both the Maryland and Massachusetts marble quarries, and during the intervening years, new layers of marble were uncovered, resulting in the slight color shift.

The Washington Monument is 555 feet 5 1/8 inches tall, and by law, is the highest point in
Washington, DC.

Dental Drills of the 1800s
  1. Wind-Up Clockwork Drill, 1864
  2. The Pedal Drill (also known as the treadle drill and dental engine)
  3. George Green's Drilling Inventions
  4. Recollections of a Pedal Drill