But the most useful mortar, of course, had trunnions and adjustable elevation by means of quoins.
quoins were blocks of wood, square, and wedge-shaped, with ring-hooks screwed in them for the greater ease of handling.
So also are the "trucks" or wheels, and the "quoins" or wedges for elevating or depressing the guns.
The rough edges of the quoins are worked with a rebate to receive the plaster which originally covered the tower.
Frequently the quoins and jambs are executed in ashlar, which gives a neat and finished appearance and adds strength to the work.
The Angles or quoins of rubble-work are always carefully and precisely worked and serve as a gauge for the rest of the walling.
Above the piece of wall which occurs between the older and newer work, the quoins of the aisleless church remain entire.
The quoins, too, in this type of wall are formed in dressed stone or brick work.
The uppermost stage is chamfered at the quoins, leaving a small off-set at the level of the next.
This is held in place by pushing in a few wooden wedges or quoins.