256 Proceedings of the Royal Society 
given by Colonel Yyse and Mr Perring, who alone ever saw them 
and measured them (for they were destroyed shortly after their dis- 
covery in 1837), but to take them, without any adequate reason 
and contrary to their mathematical measurement, as equal only to 
202 inches, and hence “ accept 9152 inches as the original length 
of one side of the base of the finished pyramid.” He deems, how- 
ever, this “ determination ” not to be so much depended upon as 
the measurements made from socket to socket. 
The mean of the only four series of such socket or casing stone 
measures as have been recorded hitherto by Jomard (9163), Vyse 
(9168), Mahmoud Bey (9162), and Inglis (9110), amounts to nearly 
9150. The first three of these observers were only able to measure 
the north side of the pyramid. Mr Inglis measured all the four 
sides, and made them respectively 9120, 9114, 9102, and 9102, 
making a difference of 18 inches between the shortest and longest. 
Professor Smyth thinks the measures of Mr Inglis as on the whole 
probably too small, and he takes two of them, 91 14 and 9102 — (but, 
strangely, not the largest, 9120) — as data, and strikes a new num- 
ber out of these two and out of the three previous measures of 
Jomard, Yyse, and Mahmoud Bey, from these five quantities 
making a calculation of “means,” and electing 9142 as the proper 
measure of the basis line of the pyramid — (which exact measure 
certainly none of its many measurers ever yet found it to be) ; and 
upon this foundation , “derived ” (to use his own words) “from the 
best modern measures yet made,” he proceeds to reason on, “as 
the happy, useful, and perfect representation of 9142,” and the 
great standard for linear measure revealed to man in the Great 
Pyramid. Surely it is a very strange standard of linear measure 
that can only be thus elicited and developed — not by direct mea- 
surement, but by indirect logic, and regarding the exact and pre- 
cise length of which there is as yet no kind of reliable and accurate 
certainty. 
Lately, Sir Henry James has shown that the length of one of 
the sides of the pyramid base, with the casing stones added, as 
measured by Colonel H. Yyse — viz., 9168 inches — is precisely 360 
derails, or land cubits of Egypt ; the derah being an ancient land 
measure still in use, of the length of nearly 25J British inches, or, 
more correctly, of 25*488 inches ; and he has pointed out that in 
