72 
and insufficient data; but adds, “ Were we to assume 6 inches 
in a century, the burnt brick met with at a depth of 60 feet 
would be 12,000 years old.” 
Again, quoting from Mr. Horner's paper the statement of 
Linant Bey finding a fragment of red brick in the Rosetta 
branch of the Nile in the parallel of the Delta at a depth of 
72 feet, then taking M. Rosiere's mean rate of deposit in the 
Delta at 2*4 inches per century, and estimating this at 2^ 
inches, he says that this work of art must have been buried 
more than 30,000 years ago. To a superficial reader, Sir C. 
Lyell would seem to adopt these two dates of 12,000 and 
30,000 years, because they are the only dates he gives in his 
account of the Nile deposit. Yet a careful perusal shows how 
carefully he guards himself, so that while an impression may 
be formed by the hasty reader that Sir Charles accepts these 
dates, he leaves us in doubt whether he agrees with Mr. 
Horner in rejecting them. But, if rejected, he must be taken 
as admitting that nothing whatever with regard to the anti- 
quity of the human race has been determined by the Nile 
deposits. 
If, however, the results of Mr. Horner's experiments go to 
prove anything at all, they give a much higher rate of annual 
increase of the Nile mud than has hitherto been assigned. If 
a work of Greek art not more than 2,000 years old has been 
brought up from a depth of 40 feet, this would give a rate of 
increase of 2 feet per century. This seems to be confirmed 
by a fact stated by Sir Gardiner Wilkinson. He has seen 
pieces of the alluvial deposit left on a rock and dried in the 
sun after one inundation. Such pieces assume a concave form 
almost like a piece of pottery, and are three-eighths of an inch 
in thickness ; this, too, taken from rock at the extreme range 
of the inundation at Thebes, where it would be much thinner 
than on the plain, where the deposit would be greater. This 
would give 3 feet per century as the mean rate of deposit, an 
inference incidentally confirmed by a passage in Mr. Horner's 
paper, where he states, p. 68, “ As a proof of the more rapid 
deposition of the heavier particles, even so low down as Cairo, 
I may mention, that at the ebb of the river after the inunda- 
tion of 1853, it was found that the deposit on the Mastaba or 
landing-place of the Rhoda Nilometer, that is, at the 9th cubic 
mark on the column, was 6 inches in thickness ; on the 4th 
step above it about 2 \ inches; and on the 16th step not more 
than 1J, each step being rather more than 9 inches deep.'' 
Now, bearing in mind that Cairo is ten miles nearer the mouth 
of the sea than Memphis, three-eighths of an inch cannot be 
taken as an extravagant estimate for the annual deposit. 
