270 
Mortar , 
The foundation being dug out the required width in 
proportion to the thickness of the wall, a strong frame of 
boards was placed on each side. The space between the 
boards filled up with any kind of stone most convenient 
and at hand, thrown in promiscuously. The interstices 
of large stones, were roughly filled in with smaller ones. 
Mortar made from fresh burnt lime and fine sand, being 
made into a paste sufficiently thin to be poured, was pour- 
ed in upon the loose stones, and thus filled up every crack 
and crevice. In a few hours, the boards were moved 
forward to form a caisson for another part of the wail, 
and the joints of the stones where the grouting had ex- 
uded, were trimmed off. Many of the strongest and 
most durable of the very old buildings in England, were 
manifestly so constructed. 
Where work is intended to be solid and substantial, 
grouting at every course is indispensable. It is indis- 
pensable also in all arch work : in England it is never 
omitted in arches. It never ought to be omitted in such 
cases, or in cut groin- work. 
Brickwork in cellar walls, or cellar arches, never dries 
if the mortar be not good, and used fresh, before it lias 
become effete. 
All these remarks are still more essential in the build- 
ing of public works, as fortifications, than in private dwel- 
lings. By attending to these directions, a wall of equal 
thickness will have more than double the strength it usu- 
ally has, built in a common way : and the mortar or ce- 
ment, moreover, will harden incomparably sooner. Wa- 
ter used to make a paste of pounded limestone (common 
mortar) and sand, can only be gotten rid of, from the 
middle of a thick wall by the slow evaporation of many 
years : but if the lime be really lime, and well and recent- 
ly burnt, all the water even of grouting, is rapidly con- 
sumed as water of crystallization. 
