Warren's Shaft

The letter ends: "The discovery of a shaft down to the water of the Virgin's Fount threw considerable light upon the object of the rock-cut canals about Jerusalem, as proving them as, had been conjectured by some, to have been for conducting away the refuse and blood from the temple.

"[2] The Old Testament (2 Samuel 5:8, 1 Chronicles 11:6) states that King David conquered Jerusalem from the Jebusites, after Joab had gained secret access to the walled town through a feature called in Hebrew the tsinnor.

[5] The wider meaning of the term includes four sections in sequence: It is generally believed that the 13-metres-high shaft is a natural karst "chimney".

[8] If so, the vertical shaft connecting the channel was designed to permit access to the canal or culvert for both construction and maintenance, as well as to afford light and ventilation.

[9] The hard dolomite rock around the Gihon Spring pool is honeycombed with natural karst fissures through which groundwater percolates.

At various times, some of these fissures were utilised as aids in the digging of tunnels and channels to control the flow of subsurface water, and especially at the Gihon Spring.