Chap. VIII.
453
“ These courses are to be laid headers and stretchers alternately; the headers not to be lessthan 2 feet 6 inches wide in the face, and run generally through the whole thicknessof the wall, but no stone to be less in the bed than 3 feet 6 inches long; the stretchers are
not to be longer than 5 feet, nor less in breadth, on an average, than 2 feet 6 inches, and nostone less than 2 feet broad : and whenever a header or stretcher is used less than thedimensions above given, the next stone is to exceed the average dimensions as much as thestone in question is under it. The backing is to be of the best Bramley Fall, Painshaw,Derbyshire, or other stone equally good, and laid in courses in thickness corresponding tothose in front. The top of each course throughout to be dressed off smooth and evenbefore the next course is commenced. The horizontal joints or beds of all the spandrilcourses are to be rusticated as before ; the vertical joints to be plain and fair-dressed, andthe outside face to be fair hammer-dressed; the interior joints to be square, close, and well-fitted. The covering or cap-stones on the point of the piers to be fair-dressed on the exte-rior and on the beds and joints, and they are to be secured to the facia course below withproper sized stone dowels 6 inches square, and to be of the best granite, as before described.The whole to be set in mortar hereafter to be described.
“ Buttresses. _There is to be a rectangular buttress over each pier and abutment, as shown
in the drawings, the outside to be faced with the best granite for at least 3 feet 6 inches in-wards ; the plinth or lower part to be plain and fair-dressed on the face ; the faces andbeds and joints to be properly dressed, and secured to the course below with sufficientstone dowels, and the masonry above to be in courses corresponding with those of the span-dril walls, and header and stretcher courses alternately ; the backing to be composed of thebest Bramley Fall, Painshaw, Derbyshire, or other stone equally good, laid in courses equalin thickness with the front or outside courses, and to be straight, square, and fair punched inthe joints, and dressed on the beds; the top beds of each course to be dressed off smoothbefore the next course is commenced, and the horizontal joints of the outside courses are tobe rusticated as before, and the faces hammer-dressed in every respect as the spandrilwalls.
“ The outside of the abutments and wing-walls above the springing of the arches is to beexecuted in every respect as described in the drawings, to be faced with the best granite, asbefore mentioned ; to be upon the average not less than 3 feet 6 inches, and to be backedwith Bramley Fall, Painshaw, Derbyshire, or Red Castle stone. The wing-walls to be ofthe thickness described, and the backing to be in courses corresponding in thickness with
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