York Herald - Saturday 24 November 1855
DEFENCES OF THE THAMES.
The martello tower, off the Isle of Grain, erected by Kirk and Parry, of Sleaford, is completed, and was, on Saturday, given up to the Ordnance. This tower has been nearly two years in erection. The peculiar construction gives it the facility of firing the guns (which are to be of the largest calibre) on traversing centre pivots so as to do execution in the fair-way of the Thames and Medway. With the latter river this tower forms a cross-fire with the Sheerness Battery guns, sufficient to sink any ships attempting to pass. The tower is struck from seven different centres, to give stability to the assailable parts. The average thickness of the solid masonry is 12 feet. The outer dimensions are 63 feet by 71 feet; underneath is a barrack-room capable of accommodating thirty gunners, and an officer's private room. The basement story contains the following rooms:— Ordnance store, provision store, barrack store, regimental store, and magazine, the latter being encased with an entire coat of asphalte. The whole of this basement is lined with 9-inch brick-work, all being within a 12-feet wall of masonry. The estimated cost of this tower is about £14,000, exclusive of its foundation of piles, which support solid balks of timber, with York landings, being filled in to a depth of 6 feet with cement. The extreme height of the tower is 41 feet 6 inches. From the exposed situation of the tower, which is subject to the sea and weather, great difficulties were experienced during the winter in proceeding with the work.
