The semi-weekly messenger. [volume] (Wilmington, N.C.) 1897-1908, 1904-12-09
The Swift Specific Company, Atlanta, &c.
REPAIRING GRANTS TOMB.
WATERPROOF Process Used 10 Ares,
Decay.

In order to prevent further DANCE
from leaking to the interior as well as
the exterior of Grants tomb it has
been decided to render the monument
waterproof, and the work of preserva-
ton has already begun. The system
used is Identical with that employed
in saving the Obelisk in Central Park.
1t consists in filling all the pores and
intersticeS of the stone with paraff1n,
which is unaffected either by acids, by
alkalies, by water or by the gases in
the atmosphere. The melting point of
paraffin wax is bou 40 degrees Fab
renheit, SO the stone, to undergo the
waterproofing, must be heated by hot
compressed air to a temperature a
little above this.
The parafin wax is then melted and
sprayed owe the surface, and this
coating is finally driven by compressed
air into the pores of the stone to a
depth Of about a quarter of an inch.
]. is estimated that by means of this
treatment stone may be kept in a state
of excellent preservation for a hun
dred "a or more.
For some time past Grants tomb
has been leaking so seriously that it
mas caused anxiety TO us dTcIlileCt,
John H. Duncan. The leaks, which
recently have been rapidly growing,
are to be found chiefly under the por-
tico at the entrance and through the
ceiling Immediately under the columns
that circle the drum of the dome.
After the heavy storm a week ago
last Sunday new leaks were discover
ed in the dome itself. These are par
TALLY dangerous, as the ceiling there
is covered with elabortely ornamnted
plaster work, and a very little leak
age would suffice to diSlodge n dash
it to h floor.
The damage in the portico consists
in the gradual disintegration, though
erosion, of the under side of the stone.
A curious growth Of minute stalacti-
ties has also been formed here from
lime washed out OF the cement by the
leaking rain.
In explaining the necessity of treat
ment for the tomb Edward M. Caffe!,
under whose direction the work is be-
ing done. said:
"It is a common misconception that
the leaks in a ton building find their
path through the joints and not
IIIouSh lIS Slol1 INcSlI. pAo'O
how pervious to water even granite is,
let me show you the practical expert
ment of wetting the upper size &c .
| small piece. In five nlinutes you will
be able both to see and to feel the
water On the lower side. Since this
| piece of granite is SO nervious to wa
| ter, you can conceive the danger even
for Grants tomb, which is built of p
| standard granite, supposed to be able
| to resist the weather better than any
other stone.
Now. the action of water or stone
is injurious in several ways. In the
first place, if the water that has pene-
trated into the intersticeS of a block
of stone freezes, it expands, naturally,
with such force hat it must make the
stone split. In the second place. water
that leaks through stone finally disin-
tegrates and decreases it's crushing
power.
"Curiously, leaking water never in
lures the side of the tone at which il
enters. 1t is only after it has perco-
lated through the stone, and so alb
sorbed some silica, hat it become:
injurious. For when the water reap
pears on the lower side. it deposits il:
particles of silica just within the pore'
OF the stone. These particles, grad
ually accumulating, form crystals
which split the stone up n MAKE
it especially dangerous in a menu'
ment such as Grants tomb, where ths
stone needs all it's crushing strength
to support the weight o it--Nev
York Evening Post