SPECIFICATION' OF WORKS.
Mason's IFork.—" Specification of the mason's work of the abutments for the iron bridge intended to be erected over the river Trent, at a place commonly called 1 high Bridge, near to Handsac•e in the county of Stafford :— " The footings to be in 3 courses, laid on level beds; the courses to be not less than 1 foot thick, and the front or out side courses to be laid header and stretcher alternately ; the stretchers to be not more than 4 feet long, and to average 2 feet in width upon the beds; the headers to average 4 feet in length, and 2 feet upon the beds; the stones to be all properly worked on the beds, that is. to have a tool draught round them, and dressed off fair between with a point or pick : the joints or ends of the stretchers to be squared their whole length, and the joints of the headers squared in the width of the stretchers, and the other parts dressed or squared with a pick ; all the space between the courses to he lilled in with ashlar of the same thickness as the outside courses, the beds prepared as before directed, and tiles ides and ends squared with a pick, and laid in proper bond to fltll in with the outside ewirses, and when a course is finished, to be grouted ; the whole surface is then to be dressed off level before another course is begun to be set.
The front courses of' these abutments, cutwaters, and wing-walls, to be not less than 1 foot thick ; laid on level beds with bond, that is, the joints to overlap about S inches, header and stretcher alternately ; the headers to average 3 feet t inches wide ; the stretchers to he not more than 4 feet in length, and I foot 11 inches wide. The beds of the ' stones to be all worked fair. and the joints squared the width of the stretchers, and the face of them clean-tooled. The wing-walls to be built curvilinear on the plans, finishing with octangular piers, and in a curve line 3 feet in the hole height ; the joints to be rusticated.
The hearting of the abutments, that is, between the ont side courses to be worked, to fall in with the radii of the arch, as shown on the section. The stone composing this
part of the abutments, to be about 1 foot thick ~there they terminate at the bottom, and when they extend to require stones more than 1S inches thick, they may be in two courses if required ; the stones must average not less than 2 feet upon the beds, and from 3 to 4 in length ; the beds to be fair dressed by a tool draught round. and dressed off between with a pick ; the headings and side joints squared and set in pro per bond as before expressed ; and when one course is set. it must he dressed off fair to its radii, and grouted before another course is begun.
The springing-stones, that is, those on which the spring ing plates of the arch are to rest, to be 4 feet, on the thee on which the plates rest ; the projection, or string-course, to be worked on the Sarni! stones. These stones to be not less than 3 feet on the beds.
"The cornice and plinth of the wing-walls, and piers, to be worked according to drawings. that is, to match the iron cornice. The caps of the piers and cntwaters to be each in one stone, and worked as shown on the drawings.
" To be a puddle of clay 3 feet thick put in against the back of the abutments, and wing-•alls carried up with the masonry as it proceeds, and filled in behind with spoil (got out from the foundations) to the extent of the wing-walls, and well rammed down to keep the puddle in its proper place.
" The stone to be used for the works to be got from Tixall or Western quarry, or any other of as good a quality ; it must be free from elay-holes or dry rents, and all to he set on its natural or quarry bed.
"The mortar to be composed of barrow lime and river or drift sand, two parts of sand to one of lime ; mixed up in small quantities, as it is used, with as little water as possible, and well heat with a beater before it is used. The grout must be made with the same lime mixed up with coarse sand and small gravel, in the same proportion as above mentioned.