PARK AND CEMETERY . 
410 
CLEANING AND PRESERVING OLD MONUMENTS 
The cleaning and preservation of old monuments is 
a matter of much importance in cemeteries of any age 
and is sure to present itself to every cemetery in a more 
or less acute form sooner or later. Monument dealers 
have in a number of instances made a business of reset- 
ting and repairing stones in old cemeteries and might 
profitably give attention to experimenting with the 
cleaning of old monumental work and the rehabilitating 
of ancient cemeteries generally. 
Frequently when marble is exposed, as in a cemetery, 
where it is more or less sheltered by trees, it is disfigured 
by lichens and other vegetable growth. 
In many instances this growth has died and become 
brown or black in color. Prof. F. P. Dunnington, of the 
department of chemistry of the University of Virginia, 
informs us that all such discolorations may be readily 
removed by soda lye of moderate strength, about 5 per 
cent. That which is rotted is dissolved and the remainder 
is soon disintegrated. 
Prof. Dunnington has made careful experiments with 
marble cleaning solutions and had occasion to give thor- 
ough tests to his preparations in cleaning the marble 
stones in the little cemetery at Charlottesville, Va., where 
the university is located. 
His method of preparing and using the solution men- 
tioned was as follows: A box of concentrated lye, con- 
taining about twelve ounces of caustic soda, is dissolved 
in a two-gallon bucket of water. Spread this over the 
stone with a small cheap scrubbing brush, made with 
vegetable fiber, preferably provided with a handle so as 
to avoid getting the lye upon the hands, the clothes or 
the shoes. After ten minutes or more pour water over 
the stone to wash off most of the lye and then rub it a 
little with the brush, using some sand if necessary, and 
the stain will be removed. 
Of course, this liquid has no effect upon the stone itself 
and is easily washed away. So far as the wash falls 
upon the ground, it will improve rather than harm any 
grass or other plants. Should the lye remain upon the 
skin, it may occasion an ugly sore. If splashed upon the 
clothing, the prompt application of a solution of sal 
ammoniac will prevent corrosion of the goods. In his 
work this treatment cost about 25 cents for each stone. 
Bellefontaine Cemetery, of St. Louis, has also gi-\'en 
much time and expenditure to conducting experiments for 
cleaning monuments, and has recently issued a circular 
which they have sent to monument makers and cemeteries. 
In addition to the method of Prof. Dunnington, Prof. 
J. W. Mallett, of the University of Virginia, describes 
the following experiments made by him at the request of 
this cemetery: 
“I have finished a series of experiments with the sam- 
ples of stones for monuments sent me by you at the 
beginning of last month. It is, of course, impossible to 
compress into a few weeks a full reproduction of the 
conditions affecting stone through a long succession of 
years. But I think you may with best prospects of suc- 
cess treat the materials you have to deal with by brush- 
ing them over carefully with a strong solution of silicate 
of soda, also commercially known as ‘soluble glass’ or 
‘water glass.’ This can best be bought in an already 
dissolved condition, which should be clear and colorless, 
or almost entirely free from, color. It should be applied 
of a consistence like that of rather thin ordinary oil 
paint. If originally as viscid as thick molasses, a little 
water may be added to bring it down to the proper con- 
sistence. To be efficient it is of the greatest importance 
that the application shall be made when the stone is as 
dry as possible, preferably after a protracted period of 
warm weather. In the case of all limestones. Nos. 1 to 6, 
inclusive, of your samples — this is the only solution to be 
used; but in the case of No. 7, sandstone from Warrens- 
burg. Mo., after the silicate of soda has soaked into the 
surface, and dried, it should be followed by a solution 
(of the same thin paint consistence) of chloride of cal- 
cium. The chloride can be bought in solid form, should 
be selected free from any distinct color, and should be 
dissolved in a small quantit.y of water to give the right 
consistence. Both the materials mentioned are cheap, 
and easily procurable from any dealer in chemicals. No 
marked effect on the appearance of the stone is to be 
feared, but when both chemicals are used there is liable 
to be a slight frost-like efflorescence on the surface, 
which is gradually washed away by subsequent rains. 
The Warrensburg stone is so deficient in cohesive strength 
that its use should be avoided, I think, for the future. 
■‘As an alternative for the above treatment with silicate 
of soda, which I am inclined to believe you will find most 
efficacious, you might try brushing over the stone with a 
nearly saturated solution of hard paraffine in gasoline. 
With the paraffine and gasoline I have (the latter boiling 
at about 45 to 50 C.), and at the temperature of the last 
two or three weeks (about 20 C. indoors), such a solu- 
tion requires about 12 or 13 ounces of paraffine to the 
gallon of gasoline. In this case also it is of the first im- 
portance that the application be made when the stone is 
thoroughly dry and, as far as possible, heated by the 
sun’s rays. 
“Whichever of the two methods be adopted it will be 
necessary to renew the application of the preservative 
at considerable intervals. If the first brushing over be 
carefully done, with the stone in proper condition, it will 
probably not be necessary to repeat the treatment short 
of at any rate a year or two. It will be well before ap- 
plying either preservative to give the surface of the 
stone a good scrubbing with soap and water (to remove 
soot, etc.), leaving ample time for drying afterwards.” 
Prof. E. H. Keiser, of Washington University, St. 
Louis, writes as follows of a method he has developed: 
“On Sept. 17, 1909, you wrote to me in regard to find- 
ing a preservative for marble or other stone, not granite, 
which could be applied to monuments, etc., in the ceme- 
tery to prevent their disintegration by the action of the 
elements. .Shortly after receiving your letter I began 
some experiments for the purpose of comparing different 
preservative agents. I coated slabs of marble with soluble 
glass or sodium silicate, with cement filler and spar var- 
nish. Then I exposed these slabs on the roof of the 
chemical laboratory to the action of the weather. During 
the winter the slabs were repeatedly covered with ice 
and snow, then thawed out and frozen again and again. 
Thus far the cement filler and spar varnish has stood 
the best. The sodium silicate has been pretty well washed 
and worn aware The varnished slab is practically as 
smooth and glossy as when first exposed. 
“I would recommend one coat of waterproofing cement 
filler, a thin varnish made by the Sherwin-Williams Co. 
(85 cents per gal., or 75 cents per gal. in barrels) and 
two coats of spar varnish made by the same company 
and sold at $3.00 a gallon.” 
