THE TOOLS OF THE PYRAMID BUILDERS. 343 
tool working from a fixed center in the the axis of the lathe, with a radius of 3.94 
inches. " Having cut this spherical carve, the center of play of the tool was shifted 
about .5 inches higher, and .7 inches out of the lathe axis, and a fresh arc on the 
bowl was struck from this centre, thereby cutting out a fresh curve which left a raised 
lip around the edges. The proofs of this explanation of the process are found in 
the exact equality of the two curves, — that of the bowl in general and that under 
the lip, — in the fact of the principal surface exactly coinciding with the inner 
edge of the lip, in the fact of the circularity of the section curves, and in the cusp 
formed where they meet, an awkwardness which no hand-turner would ever take 
the trouble to make, but which necessarily results from a sudden change in the 
centre of the arc of the tool. All these details have been worked out by the 
author from very careful measurements of the fragment, using successive templates 
of slightly varying radius to measure the exact curvature, etc. 
In addition to the tools we have alreadj^ described, graving instruments were 
employed in the production of intricate forms. Blocks of stones were likewise 
hammer-dressed; sometimes saw nicks were cut one-half an inch deep round a 
block; and then the hammer-dresser was left to work the surface down to the 
plane of the grooves. Also on sawn blocks the surface to be placed in contact 
was usually hammer-dressed to have sufficient space to hold the cement, while 
the edges were left quite smooth. For dressing surfaces to a true level, the reg- 
ular custom of the workmen was to use a trial or face-plate prepared as a true 
plane and smeared with red ochre ; wherever the ochre eame off on the stone 
they knew there was an excess and accordingly dressed it off". The tool used 
appears to have been a sort of small adze, with which the stone was sliced down 
very delicately and regularly by hand. All the blocks of the Great Pyramid cas- 
ing were prepared with these facing plates, as may be seen by the remaining 
touches of ochre on the prominent points. Not only on building stones, but 
also on rock-dressing the same ochreing is visible. Where the stone was much 
larger than the facing plate, as was the block of granite over the king's chamber 
doorway, about 8x12 feet, then a diagonal draft was cut along the stone from 
■corner to corner, and thus any wind in the plane of the face was avoided. In a 
painting at Thebes the workmen are apparently shown chiseling down a stone to 
a plane face ; they have a string stretched quite clear of a stone over an offset 
block at each side, and are then applying an offset piece to the face of the stone 
to see whether the face is in excess. This is a skillful method of working, as the 
excess does not bulge out the string, and can be exactly measured as they pro- 
ceed, while the string does not need to be removed, as the chisel can be used 
under it. Workhig on a vertical face, the beveling of the string does not af- 
fect it. 
This completes the list of Egyptian tools dealt with by Mr. Petrie, but he 
adds many interesting details of the methods of building and quarrying, which 
however, we can hardly notice as fully as the tools, since they do not present so 
great a novelty. The centre line of passages and stone blocks were carefully 
marked in red to guide workmen, and reference marks were added in case the 
