t an item that the
old builders could not go far for their stone; hence we see that the
old churches of part of Lancashire and most of Cheshire, and a large
portion of Shropshire, are of red sandstone. Some of it has stood very
well, while some has decayed into shapeless masses. There is a
tendency to exfoliate parallel to the exposed or worked surface, in
all stones, irrespective of the way of the bed, but more so where the
stone is set up on edge, or at right angles, to its quarry bed. It is
interesting and peculiar to see in some of the old buildings erected
with pebbly sandstone how the white quartz pebbles stand out from the
surface like _warts_. This is due to the greater indestructibility of
the quartz pebbles, and the weathering away, or denudation, of the
sandstone face.

Before leaving the subject of local sandstones it will be necessary to
refer to one quality they have which is of excellent utility as
regards the storage of water, but which is decidedly a disadvantage in
building stone--that is, their porosity. I have proved by actual
experiment that a cubic foot of Runcorn Stone will take up three
quarts of water by capillarity, and that it is possible to make a
syphon of solid sandstone which will empty a vessel of water into
another vessel by capillarity alone.[2] This shows the absolute
necessity of damp-proof courses, not only in the main walls of
buildings of stone, but even in fence walls, for the continual sucking
up of moisture from the earth, and its evaporation at the surface of
the stone, make it rapidly decay. I think I could show you this fact
in almost any stone building in Liverpool or elsewhere where the stone
is in direct connection with the earth. It also shows the necessity of
taking care that no stones go through the wall to the interior
surface, and of precautions for backing up stone walls with less
porous materials, or the introduction of a cavity. If you could
suppose such a sandstone wall 40 feet long, 20 feet high, and 1 foot 6
inches thick fully saturated, it would hold almost a ton of water! Of
course, it never would be fully saturated, because of the evaporation
from the surfaces, but with a southwest aspect, and very wet weather,
it might become half saturated. But what does evaporation mean? It
means the loss of so much heat and the burning of so much coal to
supply its place. From this it will be seen that a pure sandstone wall
is a thing to be avoided.

The subject is so