The following is extracted from a PDF of Vyse's Vol 1. Pages 275-6

The copy & paste I used is not perfect but it is readable.

OPERATIONS CARRIED Oi\ AT THE PYRAMIDS OF GIZEH IN 1837:
By colonel HOWARD VYSE.
and Mr. Hill discovered a piece of iron in an inner joint,
near the moutli of the southern air-channel, which is probably
the oldest piece of wrought iron known.' It has
been sent to the British Museum with the following
certificates :
—
"This is to certify, that the piece of iron found by me near the
mouth of the Air-passage, in the southern side of the Great Pyramid at
Gizeh, on Friday, May 26th, was taken out by me from an inner joint,
after having removed by blasting the two outer tiers of the stones of the
present surface of the Pyramid ; and that no joint or opening of any sort
was connected with the above-mentioned joint, bj' which the iron could
have been placed in it after the original building of the Pyramid. I also
shewed the exact spot to jNIr. Perring, on Saturday, June 24th.
"J. R. Hill.
« Cairo, June 25th, 1837."
" To the above certificate of Mr. Hill, I can add, that since I saw
the spot at the commencement of the blasting, there have been two tiers
of stones removed, and that, if the piece of iron was found in the joint,
pointed out to me by Mr. Hill, and which was covered by a larger stone
partly remaining, it is impossible it could have been placed there since
the building of the Pyramid.
" J. S. Peering, C. E.
« Cairo, June 27th, 1837."
"We hereby certify, that we examined the place whence the iron
in question was taken by Mr. Hill, and we are of opinion, that the iron
must have been left in the joint during the building of the Pyramid,
and that it could not have been inserted afterwards.
" Ed. S. Andrews,
"James Mash, C. E."
The mouth of this Air-channel had not been forced—

Regards to all,

Robin