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XL. Account and Description of a Hollow Wall, erected in 

 the Garden of the Earl of Arran, JP. H. S. atBognor, in 

 Sussex. In a Letter to the Secretary. By Mr. Henry 

 Stlverlock, of Chichester, F. H.S. 



Read, March 21st, 1820. 



Sir, 



In compliance with your request I send you the following 

 detail respecting the Hollow Wall which I have erected for 

 the Earl of Arran at Bognor. It is built nine inches 

 thick, with sound even-sized bricks, placed edgeways, the 

 joints being carefully made, and laid with the very best 

 mortar. The bricks are placed with their faces and ends 

 alternately to the outside, so that those which have their 

 ends exposed become ties to the surfaces of the wall. In 

 each succeeding course, as the wall is built, the bricks with 

 their ends outwards are placed on the centre of the brick 

 which is laid lengthways in the course below it. Thus a 

 hollow space is formed in the middle of the wall, of four 

 inches width, which is only interrupted where the tying 

 bricks cross it ; but there is a free passage for air from top 

 to bottom of the wall. The wall is covered close at the top 

 with a heading course of bricks, on which is a coping of 

 Portland stone, with a projection of two inches, and 

 strengthened at every twenty feet by piers of fourteen inch 

 work, executed in the same manner with bricks on edge, 

 which are so worked in, as to preserve the continuity of the 



