PARK AND CEMETERY. 
139 
ASKED AND ANSWERED 
An exchange of experience on practical matters by our readers. You 
are invited to contribute questions and answers to this department 
Weathering of Bronze. 
Editor Monumental News: We have a 
bronze tablet we placed on a cement vault 
and it has become covered with verdigris 
once and we sent it back to the manufac- 
turers and they cleaned it and shellacked 
it and returned it. It has been up about 
two years the last time and is covered 
again. Is there anything we can do to re- 
move this verdigris? Is this peculiar to all 
standard bronze ? — J B. M. 
It is to be expected that a cast bronze 
tablet would become covered with verdi- 
gris if put up in a very damp place. Any 
alloy of copper, whether it be brass, which 
consists of about 66 per cent copper and 
the remainder tin and zinc, or standard 
statuary bronze, consisting of 90 per cent 
copper and 10 per cent tin and zinc, will 
form a surface color, called by the French 
“patine,” according to the nature of the 
chemical applied to the alloy. Thus sul- 
phur fumes and an application of sulphide 
of potassium will quickly cause a reaction 
on the surface of the bronze, coloring it a 
dark brown. Statuary and architectural 
bronze work exposed to the atmosphere of 
our cities in which there is much coal 
smoke quickly turns very dark. 
The green coating on bronze is produced 
by the action of vinegar or sal ammoniac. 
If the tablet in question has become cov- 
ered with verdigris it would show that the 
moisture in the cement vault is impreg- 
nated with salts. To many people this 
surface color, whether it be the brown of 
statuary bronze or the green color of ver- 
digris, is a distinct advantage from an 
artistic point of view. For example, the 
Statue of Liberty in New York harbor has, 
under the influence of salt air, acquired a 
beautiful green color. Some practical peo- 
ple, thinking that a corrosion, a result of 
age, considered it a species of dirt and 
therefore have invoked the War Depart- 
ment to scrub down “Miss Liberty” to the 
original bronze color, all of which was 
most strenuously opposed by those who ad- 
mire the softening influence of time an4 
atmosphere on monuments, buildings, stat- 
uary, etc. 
If your correspondent wishes to remove 
the verdigris from the bronze tablet, sim- 
ply let him scrub it down with white sea 
sand and water in which there has been 
dissolved a small quantity of sulphuric acid. 
However, perhaps we had better give you 
a full recipe for cleaning bronze and re- 
storing the oxidized finish. This recipe is 
as follows : 
First, mix potash of lye with hot water. 
Apply this vigorously with a stiff brush, 
also using white sea sand. Repeat this, 
rubbing with the potash and sea sand until 
all dirt and grease is removed; then wash 
with clean water and scrub with a “pickle” 
composed of sulphuric acid (oil of vitriol) 
and water, one pound of sulphuric acid to 
a gallon of water. Be sure to pour the 
acid into the water, and not the water into 
the acid. This combination will generate 
considerable heat. Wait until it cools be- 
fore using. Scrub the tablet with sea sand 
and water, then scrub with sulphuric acid 
pickle until all discoloration, green spots, 
etc., are removed and the natural bronze 
appears. Wash off the pickle entirely with 
clean water, then use sea sand freely. The 
bronze should then be bright and clean, 
the color of a new cent. Then mix one- 
half pound of potassium sulphide with one 
gallon of water. This forms an oxidizing 
fluid which will stain the bronze to a dark 
color. If it does not stain quick enough 
or dark enough, use more of the potassium 
sulphide. After having made the first ap- 
plication of oxidizing fluid to the bronze a 
light stain is obtained. This must be well 
sanded with sea sand and washed with 
clean water. Repeat the applications of the 
oxidizing solution and the sanding down 
of same until the color is brought to a uni- 
form dark tone. It is' preferable that the 
water which is used to wash down the 
bronze after the application of oxidizing 
fluid be hot, but cold water will do. Imme- 
diately after the oxidizing fluid is applied 
and a satisfactory bronze color obtained 
and has been washed with water, use tissue 
paper to dry off the water. When thor- 
oughly dry go over the bronze with a soft 
cloth dampened with oil (any kind of oil 
will do). These solutions are poison and 
should be destroyed when work is com- 
pleted. Do not get lye or the sulphuric 
pickle on hands or clothes. 
To prevent a recurrence of the staining 
of the tablet by verdigris, referred to by 
your correspondent, some little attention 
should be paid to the bronze from time 
to time. There is no use of shellacing 
the bronze or giving it a coat of varnish. 
It must be rubbed from time to time with 
an oil dampened cloth. If this is not done 
the bronze will stain and the above treat- 
ment will be necessary to bring it back to 
a good condition. The statuary in our 
cities should be scrubbed down with lye and 
all the surface discoloration, soot, grime 
and dust removed and rubbed with a soft 
cloth dampened with oil, but, of course, 
under no circumstances should the sand be 
used on the statuary, for this would bring 
it down to the raw color of the metal. In- 
cidentally, when bronze is set up it seems 
that it is expected to retain a beautiful 
color ever after, and, of course, when the 
sculptor is all through he cannot afford to 
keep bronzes in condition, and we cannot 
count on him. 
The bronze foundrymen have completed 
their contrast in casting the work. No at- 
tention can be expected from city authori- 
ties, and the owners of fine bronze work 
never think of making an expenditure for 
proper cleaning and care which should be 
given the work from time to time. 
One of the beauties of bronze is the 
varied coloring of the surface acquired by 
exposure to the weather or to chemicals. 
The natural color of the metal is a red- 
dish golden hue, the color of a new bronze 
cent. Under the action of the elements 
this golden color soon darkens by oxidi- 
zation. If the bronze is exposed to sul- 
phur fumes or to any of the chemical forms 
of sulphur, it will take on a brownish tint, 
sometimes so dark as to appear almost 
black. Thus, in our cities, sulphur in 
the coal smoke soon turns the statuary 
practically black. The green color on 
bronze, sometimes termed “Verd-antique,” 
is brought out by the action of salts, vin- 
egar and sal ammoniac. Bronzes near the 
seashore, exposed to the salt air, usually 
are a beautiful green color. An example 
of this is the Statue of Liberty in New 
York harbor. These surface colors of 
bronze are termed by the French “patinas.” 
It matters not how old the bronze, the color 
is, like “beauty,” only “skin-deep.” Scratch 
it ever so lightly and the glowing golden 
metal shows beneath. Therefore in clean- 
ing old bronzes on monumental work or 
elsewhere, one should be careful not to 
abrade or scratch the surface of the 
bronze. If discolored with an accumula- 
tion of dirt, soot and the grime of years, 
this may be removed with plain soap and 
water. When dry, the application of a soft 
cloth dampened with oil will restore the 
bronze to good condition, and the further 
application of an oil-dampened cloth at 
long intervals will bring the bronze finally 
to a condition where the mellow tones of 
the surface coloring will delight the con- 
noisseur and lover of bronze work. 
Wm. Donald Mitchell, 
.Tno. Williams Bronze Foundry. 
New York City. 
Grass Seed for Hillsides. 
“Which is the best grass' seed to produce 
quick results on hillsides?” — J. D. O. 
Replying to your correspondent’s in- 
quiry, will state that the best seed to sow 
on side hills is English rye grass, one 
part, to two parts of blue grass. Sow 
and rake in, roll and shade with a thin 
covering of fresh cut grass from the lawn. 
Wm. Salway, 
Supt. Spring Grove Cemetery. 
Cincinnati, O. 
Judging from your correspondent’s let- 
ter, we should think he would want to 
use the hillside for lawn or cemetery pur- 
poses. At any rate, this should be sown 
in grass that would not be rough, but 
would present an even, uniform appear- 
ance at most seasons of the year. If the 
