148 THE BUILDING NEWS.
Fez. 23, 1872.
uniformly mingled together as possible. He
says it is only in the darker stones that the
colouring matter has any tendency to disinte-
grate the mass. He contends one sample is
not enough to test a quarry by, but that the
rock or place should be examined at the out-
set, and then he states his reasons, which I
am tempted to give, because from them we
gather the American view of this subject,
and also, because the value of this report in
that country is somewhat equivalent in
importance to that of our own Commission
to which I have alluded.
“For in its natural outcrops it has been exposed to
the action of the weather, in all its influences, for
many thousands of years. One of the principles
taught in elementary geology is that the soft and
decomposing rocks appear in low rounded or flattened
exposures, or entirely covered by the soil of their
own débris, forming no conspicuous feature in the
country ; while, on the contrary, the harder rocks
stand out in relief, producing marked and distin-
guishing features in the landscape. It not unfre-
quently happens that the geologist, having familia-
rised himself with the succession and character of
the rocks of a particular locality or neighbourhood
by seizing the features and character of the promi-
nent beds, is able to trace them in succession along
the escarpment or mountain range as far as the eye
ean reach, and to approach them from any distant
point with assurance that he has not been deceived.
“The strata which make these features in the land-
scape are the eyer-enduring rocks, which haye with-
stood the action of the atmosphere through a period
a thousand times longer than any structure of human
origin. One cannot doubt that, if properly placed
in any artificial structure, they would still withstand
the action of the elements. ‘These escarpments, in
their natural situation, may be coarse, rough, and
forbidding, more or less dilapidated, or unequally
dilapidated from the effects of time; but as they
there present themselves, we shall be able to see
their future in any structure exposed to the same
influences.
“Tt is true, however, that no artificial structure or
position will ever subject the stone to the same
degree of weathering influence to which it is exposed
in its natural position, but the same changes in
degree will superyene upon any freshly-exposed
surfaces. In its natural position the bed has been
encased in ice, washed by currents, saturated with
rains and melting snows, frozen and thawed, and ex-
posed to the extreme of summer heat without miti-
gation. The rock which has withstood these in-
fluences is quite equal to withstand the exposures of
a few centuries in an artificial structure. Yet there
are occasionally modifying influences and conditions
which have sometimes subdued the permanence of a
durable stone, and given preference to others less
durable. It,therefore,becomes necessary to carefully
examine all these conditions, and to determine, not
only from the rock in place, but also from its physi-
cal constitution, whether it will meet the require-
ments of the structures proposed.
“Tt not unfrequently happens, in working a quarry,
that layers are reached which have not been ex-
posed to the weather, and it is then necessary to test
the strength and power of endurance of the stone.
This may be done by repeated exposure to freezing
and thawing, by testing the strength or power of
resisting the action of the weather, but» will deter-
mine also whether such foreign ingredients as iron
pyrites may exist in the mass.
“ Chemical analysis may be resorted to for the pur-
pose of comparison with specimens of known com-
position and durability ; but chemical analysis alone
cannot determine, without other testing experiments,
the strength or power of endurance of the stone.”
Old Buildings are somewhat of a test, but only to a limited extent, as sometimes the stones of which they are built were brought from a distance, or the particular quarry has been worked out. Should the old building show decay, it may arise from the stones not having been well selected, or they came from those beds first worked at the opening of the quarry, and may not be so good as those which the quarry now produces. The difficulty of obtaining a genuine test of a stone is great, because each quarry owner who desires a chemical test is more ‘likely than not to take the sample from the best bed of his quarry, and obtain the analysis on that, and thus he has a certificate of quality which applies to the entire quarry, while, in reality, it may not apply to a twen- tieth part of the stone he sends therefrom. Some have suggested a Royal Commission to visit every quarry, take samples where they like, and test them. Mr. Trickett, who writes on the subject, and is, I think, a stone mer- chant, and therefore must have much expe-
rience, suggests that the ‘‘ practical men who
have made the subject a study, should give a
plain statement of facts,” or ‘the quarrymen
themselves give us their views;” he goes
on to say, fairly enough, ‘‘these would, no
doubt, be to a certain extent one-sided ;” but
adds, ‘‘who can speak of the qualities of a
stone like those who have worked at it all
their lives ?”
Advantages.—Appearance. Power of ya-
riety of decorative design without increase
of expense.
Disadvantages.—Decay. Expense.
Cost of producing decorative work.
The decay and difficulty of selection I
have already enlarged upon. As to whether
the former can be, by processes, patented or
otherwise, prevented, we shall hereafter con-
sider. The expense.—This I have placed to
each sort of stone. The comparative cost
will be considered in the chapter dealing
with the relative expense of building with
the various materials at our command. The
expense with regard to decorative works is
that where great quantities of the same thing
are required, each one in stone costs, of course,
about the same, while in artificial stone or
terra-cotta, amouldis made, and thus, the more
there is wanted the less is the cost of each
one. But the serious point is the damp. In
a paper read before the Liverpool Architec-
tural Society, the writer, speaking on this
point, explains it thus, that the damp which
is frequently seen under stone cills in new
buildings results from the skin of the stone
having been taken off by working the stone,
causing the water to find its way through the
stone cill to the wall beneath, and gives (as a
partial remedy) painting, stating this ‘‘ may
often be remedied by giving the top two or
three coats of good oil paint.” But I come
to the more serious cause of damp inside
stone houses, and which is frequently pre-
vented by the expensive method of a lining
inside of the walls with bricks, This is
called—
Osmatie Action —No matter what thickness
the walls, if built of limestone, they will
absorb moisture on the outside from the
atmosphere, and give out that which it has
absorbed in compliance with the law of osmus,
through the action of heat in the interior of
the house.
The increase of the heat in rooms where
walls are built of limestone, instead of drying
them in rainy weather, actually has the op-
posite effect, for the osmus is superinduced by
the attraction of the heat thus created, and
the thin surface of fine rain-water, percolating
through the stone, becomes thicker, and es-
tablishes itself in large globules on the plaster
of the inside face of wall. Damp, also, affects
all limestones by capillary attraction. ‘This
must be guarded against, or damp from the
ground will be sure to insinuate itself into the
warm rooms by way of the centre of the lime-
stone wall, even should the external face of
the wall be waterproofed by some process.
The capillary attraction may be prevented by
a waterproof course between foundations and
superstructure.
Treatment—According to the grit of the
stone must be the decoration. If this be
coarse, heavier contours with coarser arrises
and fillets. Stone does not possess that even-
ness of colour that marble does, but its very
differences of tint will, I think, be considered
an advantage. Proper effeet in carving is
obtained from bold treatment. I quote Sir
William Chambers, who sayssotruly: ‘When
objects are near and liable to inspection, every
part of the ornament should be expressed and
well finished ; but when they are much exalted
the detail may be slightly touched or entirely
neglected; for it is sufficient if the general
form be distinct, and the principal masses
strongly marked; a few rough strokes from
the hand of a skilful master are much more
effectual than the most elaborate finishings of
an artless imitator, which, seldom consisting
in more than smoothing and neatly rounding
Damp.
off the parts, are calculated to destroy rather
than to produce effect.”
I do think that much of the work of the
present day is too finely finished for the
material, and that more effect could be ob-
tained with less expenditure; but here I am
on debatable ground and would give but one
piece of advice. Remember in designing
ornament to consider where it is to be placed
and endeavour to realise the effect, or where
your decorative works are placed in situ dis-
appointment awaits you.
Preserving Processes—What is required in
any process is the protection of the stone
against the chemical action of the atmos-
phere of our towns, and the mechanical ac-
tion of winds, rains, and frost. The aspects
which suffer most severely from decay are the
south, south-western, and western fronts. As
this is generally admitted it only behoves
the architect to take especial care that the
stone of fronts haying such aspect
should be well seasoned and selected; and
then, if requisite, haye the preserving pro-
cessses most carefully applied.
Zs there any process that will do what is
required ? I am of opinion that we must
wait some time still before we can arrive at a
decision on this point and on the comparative
merits of the many systems that are before
the public. Mr. Ransome’s process is sup-
ported by a report of Professor Ansted and
many other goodmen. Professor Chureh’s is
more modern, the new patent being 1869.
There has, therefore, been very little time to
test the endurance. ‘The coatings comprise
three transparent colourless solutions. It is
usual to apply one application a day. In the
third coat or application any pigment may
be added. The softer the stone the more it
absorbs. ‘The cost for sufficient materials to
do with the threeapplications, 100 superficial
yards, is £2 2s. 6d.
The best time for the application of all
preserving materials is dry weather,
Conclusion.—I must now leaye the subject to
preserving stone, as to which there isso much
uncertainty, which must continue, [ am
afraid, until the question is taken up and
thoroughly investigated with the same patient
labour that Tredgold and Fairbairn devoted
to wood and iron.
I can only suggest that we may all derive
some little consolation, till that time arrives,
by remembering the words of Professor Don-
aldson in his opening address at the General
Conference of Architects where he says
‘Our Bath oolite is equal to that of Paris, if
only our miserable economy in some cases,
and the spirit of competition among un-
principled contractors, the stone merchants
and quarrymen themselves, did not counteract
the intention of the architect, and bring
into use the stone from inferior beds, instead
of from the soundest and best strata. There
is not a better stone than our sea-girt Port-
land, if only properly selected, whether for
its tone, its homogeneousness, or resistance
to the atmosphere. $. Paul’s Cathedral,
thanks to the precautions of the illustrious
Wren, and Somerset House, may be cited to
prove the enduring qualities of this material,
when carefully chosen in the quarries. In
these two buildings the arrises of the mould-
ings and angles, and the very carvings, still
retain their sharpness.”
I have shown how little is really known
on these subjects, and how wide a field still
presents itself for inquiry to the energetic,
painstaking student.
1. To determine which is really the best
quarry of each class. ,
2. To find whether the sand or limestone
is most enduring. .
.3. Having discovered the two preceding
points, to fix the difference of cost of the
best of each kind, so that the architect may
be able to place that important item before
his client.
4, Assuming, as present practice seems to
require (so many new buildings being at
oot
