391 
Brick-Making. 
by every change of the weather, so that the walls become 
damp, and the plastering discoloured, causing the bond 
timbers and plates to rot ; and for want of equal solidity 
with the external bricks the walls crack, the timbers swag, 
because the bearing on them cannot be then any where 
equally poisedo 
The dampness which so often affects the inside walls 
is attempted to be palliated, or removed, by the introduc- 
tion of what is called battening, w^hereby an opening or ca- 
vity is left between the brick- work or plastering ; but 
whoever has attentively observed the result of this inven- 
tion, which in very many instances has fallen to my lot to 
notice, will see that the damp arising from these bricks 
engenders mould, and is visible on the frame of the W’ood 
used in the battening ; this mould is no doubt the secon- 
dary cause of the dry rot, since the origin must be in the 
bricks themselves. 
That this is the case may be deduced from this fact, 
that wherever a quantity of those bricks is heaped up to- 
gether for any length of time, they will upon separation 
be found to have their bases covered with a fine white 
net-work, especially those which are nearest the bottom. 
Hard burnt sound bricks never have this net-work grow 
upon them, let them lay as long as they may in any situ- 
ation. This net- work then is the plantulas of mould. 
The origin and increase of mould is nearly in proportion 
to the heat of the atmosphere ; its appearance and vege- 
tation are never more sudden than during the summer, 
and the reason seems to be, that the heat of the weather ne- 
cessarily draws out the redundant moisture from the 
bricks, for want of a due circulation of air. This mois- 
ture attaches itself to the outside of the bricks, and there 
remains, the heat not being sufficient to dry it up, but 
enough perhaps to produce a degree of warmth ; it enters 
into a slow but certain process of fermentation ; and, pass- 
