This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol5", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
In Gothic buildings, in addition to a cornice moulding, the parapet is of common application, serving to hide the guttering and the junction of the roof with the wall, and also to lessen the effect of excessive height caused by a steep pitched roof. Such parapets are frequently ornamented either by crenellations or battlements, as in Fig. 148, or by tracery, as in Fig. 149.
A parapet has also a further use in cases where side thrust is to be met in the wall, tending to neutralise its effect by supplying extra weight in the abutment.
In the design for Tooting Wesleyan Chapel (Fig. 150), by Mr. J. S. Gibson, F.R.I.B.A., the angle buttresses of the tower are connected by a parapet with recessed arcadings with traceried heads, the upper portion of which are cut as battlements.
In this case the walls are not pierced for the tracery, the recessing being of sufficient depth only to afford a distinct enough contrast between the face of the wall and the panelling.