Abilene weekly reflector. [volume] (Abilene, Kan.) 1888-1935, 1888-08-23
CLEANING SToNE-WoRX.
Description of the Methods Known as
the Liebha5er Processes.

4 Description of the Methods Known a.
the Liebhaber Processes.
During the year 1886 the masonry
Ind iron-work OF the Madrid and Bau-
lin bridges at Paris were thoroughly
,leansed by Messrs. Matthew and
Peigne, who work the patent processes
Of NJ. LiebhaDer. These processes,
which are purely chemical in their
nature, were at first applied solely to
the cleaning of lime-stones, but in
these bridges materials of very diff
ferent nature were successfully dealt
with. The surfaces to be cleansed are
submitted to the action of Jet of mixed
hydrochloric and sulphuric acids, and
left for two or three hours. when they
are all well brushed, and finally
washed down with a water-jet, which
completes the process. In the case of
limestone masonry, the hydrochloric
acid unites with the calcium, forming
chloride of lime, which is then decom-
posed by the sulphuric acid forming a
calcium sulphate, this being precipi-
tated on the face of the stone, and con-
tanning all the impurities, which are
then removed by the action of the brush
and of the water-jet. In many cases
this acid treatment will not succeed
unless the stone is previously prepared,
as the masonry frequently becomes
coated with a black and shining de-
post of all the impurities contained 10
the atmosphere Of large town, which
entirely prevents the acids reaching the
stone. In this case NJ. de Liebhaber,
before applying the acids, covers the
stone with an alkaline paste, consisting
of mixture Of carbonate of soda and
calcium hydrate. which he has named
''tolugene." This paste is spread over
the face of the masonry with trowel,
to a thickness of from one-half to one
millimeter, and left there for from
three-quarters of an hour to an hour.
when the excess is quickly washed
down and brushed of. and the acids ap-
piled as previously described. In
cleaning iron-wor!l the "tolugene''
alone is used; it is spread over the
work either with trowel or brush, and
in the course OF an hour or so will have
united with all the oil of the paint,
leaving the red-lead on the work in the
form of dry powder. which can be
easily washed off with jet Of
water. The metal is said to be cleaned
much better than by the older method
of burning and scraping off the paint.
For cleansing brick-work M. de Lieb.
haber makes use of the property which
hydroHuoric acid possesses of separa.
ting the silica from silicate5. The work
is first painted with a solution of am
monium foride, and this Immediately
afterwards is treated with a jet of con-
centrated sulphuric acid, which libe-
rates hydrohuoric acid IN stu, and this
Immediately attacks the silicates, rob-
bling them oftheir silica. The whole sur
face is afterwards thoroughly washed
with water. With regard to the cost
of the processes a total of SOP square
yards of masonry, of which about 16;
were sandstone, were treated at the
Madrid bridge at a cost of from SD. to
8.4d. per square yard, and brick-work
at the Baudin bridge cost Sad. pei
square yard, the prices including the
cost of erection of such scaffolding a;
was necessary. With regard to the
iron-work, the contract price was 10d
per square yard for plain work, and Is
Sd. per square yard for moulded work
but the contractors are said to have lost
money in carrying out this part of theil