Mon 23 Nov 1829
From John R Denyer
To J S Salt
London
Had to put the Engine to work to keep up water supply in the Summit level for boats to navigate at their full depth. Much alarmed by report that portion of Tunnel had fallen in & totally stopped navigation. On inspection turned out to be a stone of about ½ ton slipped from its bed into bottom which with aid of some tackle belonging to vessels detained at the Coates end was removed in few hours. Enclosed a Fly Boat circular. Very little increase in quantity of goods carried at present.
