Washington Monument
Walls
### Walls

[thumb\|upright\=1\|Cross section of rubble in shaft at 150\-feet and typical of rubble below 150 feet\|alt\=Showing about 85 irregular large stones in mortar between empty shaft well and outer marble veneer](/wiki/File:Washington_Monument_rubble_at_150_feet.png "Washington Monument rubble at 150 feet.png")
During the first phase of construction (1848–1854\), the walls were built with bluestone gneiss rubble, ranging from very large irregular stones having a cross section of about  down to spalls (broken pieces of stone) all embedded in a large amount of mortar. The outer surface is marble stones  thick in  high courses or rows horizontally encircling the monument. Although each course contains both stretchers (stones parallel to the wall) and headers (stones projecting into the wall), about two to three times as many stretchers as headers were used. Their joints were so thin that some stones pressed on bare stone below them, breaking off many pieces since it was constructed. The batter or slope of the outer surface is 0\.247 inches per foot (2\.06 cm/m, 1°11'). The inner surface has disorderly rows of smaller roughly dressed bluestone gneiss. The base of the first phase walls has an outer dimension of  square and a thickness of . The interior well is  square and has square corners. The weight of the first phase walls up to  is .

During the second phase (1879–1884\), the walls were constructed of smoothly dressed ([ashlar](/wiki/Ashlar "Ashlar")) large marble and granite blocks ([rectangular cuboids](/wiki/Cuboid%23Rectangular_cuboid "Cuboid#Rectangular cuboid")) laid down in an orderly manner ([Flemish bond](/wiki/Flemish_bond "Flemish bond")) with thick joints. Two\-foot high marble surface stones, using an equal number of stretchers and headers, were backed by granite blocks from the 152\-foot level (the first course above the rubble) to the 218\-foot level, where marble headers become increasingly visible on the internal surface of the walls up to the 450\-foot level, above which only marble stones are used.
Between the 150\- and 160\-foot levels the inner walls rapidly slope outward, increasing the shaft well from 25 feet 1 inch square to  square with a corresponding decrease in the thickness of the walls and their weight. The second phase walls at the 160\-foot level were  thick, which, combined with the larger shaft well, yields an outer dimension of  square at that level. The top of the second phase walls are  square and  thick. The second phase interior walls have rounded corners ( radii). The weight of the second phase walls (from 150 feet to 500 feet) are . The walls of the entire shaft (combined first and second phases) are  high.

The first phase of the walls was constructed under the direction of William Dougherty. Its white [Cockeysville marble](/wiki/Cockeysville_Marble "Cockeysville Marble") exterior came from the Texas quarry now adjacent to and east of north I\-83 near the Warren Road exit in [Cockeysville, Maryland](/wiki/Cockeysville%2C_Maryland "Cockeysville, Maryland"). The quarry was named for the Texas Station (no longer extant) and 19th\-century town on the [Northern Central Railway](/wiki/Northern_Central_Railway "Northern Central Railway"). During the first phase it was operated by Thomas Symington, but is now operated by [Martin Marietta Materials](/wiki/Martin_Marietta_Materials "Martin Marietta Materials") and no longer produces building stone. The second phase of construction was under the direction of Lt Col/Col [Thomas Lincoln Casey](/wiki/Thomas_Lincoln_Casey_Sr. "Thomas Lincoln Casey Sr.") of the [United States Army Corps of Engineers](/wiki/United_States_Army_Corps_of_Engineers "United States Army Corps of Engineers"), who removed two defective courses added by the [Know\-Nothings](/wiki/Know_Nothing "Know Nothing") and the last 152\-foot course added by Dougherty before Casey began his construction. The next three courses of white marble () came from [Sheffield, Massachusetts](/wiki/Sheffield%2C_Massachusetts "Sheffield, Massachusetts"), while all courses above them came from the Beaver Dam quarry just west of the 19th\-century town of Cockeysville. The latter quarry is located on Beaver Dam Road near its intersection with McCormick Road. During the second phase the quarry was operated by Hugh Sisson, but is now flooded, is called Beaverdam Pond, and is the home of the Beaver Dam Swimming Club. Both 19th\-century towns are now within the city limits of Cockeysville.


What are the dimensions and weight of the first phase walls up to a certain height?