(15) As to the time which would have been taken to complete the trench, it is interesting to get a rough approximation.
Assuming that, with rammers, the men can extract 8 millimetres in an hour in each quarter of their double-foot task, then the time taken to complete the trench, with an extra metre for undercutting, will be that of working it at its deepest part, that is to a depth of 4.2 + 1.0 metre, and will equal (4 × 5.2)/(.008 × 12 × 30) months of twelve hours per diem = 7.22 months.
Before leaving the subject of time taken, we might apply this calculation to the obelisk of
atshepsôwet, assuming that it was detached in much the same way. Here the deepest part of the trench is 2.40 + .75 metre [8]; then the time taken would have been: (4 × 3.15)/(.008 × 12 × 30) = 4.4 months. {15}
[8] Since the obelisk is smaller.
It is recorded by the queen that “they are of one block of enduring granite, without seam or joining. My Majesty exacted work thereon from the year 15, the first of Machir (6th month), until the year 16, the last of Mesore (12th month), making seven months of exaction in the mountain.” Allowing for undercutting and a certain amount of top clearance, our calculation seems within the bounds of reason.
During the work of trench-pounding, the top-dressing, embankment preparing, and clearing for the exit of the obelisk would be carried on.
CHAPTER III. THE UPPER QUARRY-FACE.
(16) At the south-west corner of the obelisk there is a kind of platform, sloping down southwards towards a vertical face of rock. Plate [II], no. 2, shews the obelisk with the platform at the right, and plate [V], nos. 1 and 2 shews the rock face viewed from below the north side of the obelisk, and from directly opposite it. A detailed drawing of the markings on the quarry-face is given on plate [VI].