Evening star. [volume] (Washington, D.C.) 1854-1972, 1857-07-16

IN IhE bNIENSIpN OF IHE DNlIkD
CkPITOL.''-An interesting and valuable paper
with the above heading, prepared by Professor
Henry, was read before the American Association |
for the Advancement of Science, at its late meet
ing, and will be included In the forthcoming
Smithsonian report.
From it we gather a great number Of facts Of
general interest. A commission was appointed
by the President of the United States. in Novem-
her, 1851, to examine the marbles which were Of
fered for the extension of the United States Cant
tol, consisting of Gen. Totten, A. J. Downing,
the Commissioner Of Patents and Prof Henry
Another commission was subsequently, appointed
IN the early part Of the year ISL to repeat and
extend some OF the experiments the members Of
WHICH were Gen. TOtten, Prof Bache, Captain
Mefgs, and Prof. Henry
The art OF testing the quality of stone for build
ing purposes Is al present in a very imperfect
state; the object is to initiate the operations of
nature and At the same time to hasten the effect
by increasing the energy of the action. 1t
should be recollccted that while the exterior
materials OF building are TO lie exposed for CEN
tuIles, the conclusions desired are to be drawn
from results produced in the course of few
weeks. Besides this. in the present state of sci
ence, we do not know all the actions TO which the
materials are subjected in nature nor can we fully
estimate the amount Of those which are known
lie solvent power of water, which even at
tdCkS glass. must in time produce an apDreciahIe
effect ON the most solid material PARTICULARLY
where u contains, a. the water of the atmosphere
Always does, caTbonlC acid in solution. The at
Triton of siliCiOus duSts. when blown against a
bhlidlnS, or washed down its sides by rain. is
tEldenuy operative in wearing away the surface,
Time may not be indicated by the incest balance
An examination of the basin which formerly re-
ceived the water from the fountain at the western
entrance Of the Capitol, deposited in the
Patent Office, Will convince any one of the great
amount of action produced principally by water
charged with CarbOnic acid. Again. every flash
OF llg htning not on v generates nitric acd-whch
IN solution in the rain, acts on the marble-but
also by Its inductive effects a distance produces
chemical changes along the moist wall which
are at the present time beyond our means of esti-
mating. Also, the constant variations of temper
atuEe from day to day. and even from hour to
hour. give rise To molecular III, tons which must
affect the durability of the material of 7 build
ing Recent observations on the pendulum have
SHOWN that the Bunker Hill monument is scarcely
Tor moment in a state of rest. but is constantly
Wrapping and bending under the influence of the
cveI-varying temperature of its different sides
me marble chosen for the Capitol is dolo-
mite, o., IN other words is composed Of carbonate
OF lime and magnesia in nearly atomic propor-
tionS. f'P
The marble is obtained from a ouarrv in the
eoutheaSterIy part of the town OF Lee in the State
OF Massachusetts and belongs To the great deposit
OF primitive Limestone which abonnds i'm that
par OF me district II is generally white, with
occasional blue veins. The structure is fine
grained Under the microscope il exhibits fine
crystals OF colorless mica, and occasionally also
small PARTICLES Of biSu phuret of iron ItsIstains
@3SI' IDS 10 the square inch. IL not only abSorbs
water by capillary attraction but in common with
other marble suffers the diffusion of gases to take
place through its substance. DIR. Torrev found
That hydrogen and other gases separated from
each other by slices of the mineral diffuse them
serves with considerable raPidity through the
The marble. soon after the wo-kmen commenced
placing ii in the walls. exhibited discoloTation
T1 orownish hue 10 trace of which appeared so
long as the blocks remained exposed TO the air in
the >tOneCutter'S yard. A variety of suggestions
ana experiments were made in regard to the
cause OF this remarkable phenomenon. and it
nhally concluded that II was due to the previous
absorption by the marble of water holding IN So
luton small portion Of organic matter together
win me absorption OF another portion of water
from the mortar.
Moreover, as soon the polished surface of a
building Is made rough from any Of the causes
aforementioned, the seeds of minute lichens and
Inosses. which are constantly floating i'm the at
moSpheIe, make ii a place of repOse and from
the growth and decay OF the microscopic plants
which spring from these diScolOTation is pro-
duced, and diSintegratiOn assisted But perhaps
Tie greatest source of dilapidatiOn in climate
like ours is that Of the aIternafions of freezincr
and thdwing which take place during the winter
season; but though the effect of this must DE
comparatively large, yet in good marble, il re-
qulfeS the accumulated results of d number of
years in Order definitely to estimate its amount
TO illustrate the process let us suppose fine
capillary tube, the lower end Of it immersed in
water and of which the Internal diameter is SUf-
hciently small To allow the liquid to rise TO the
Is TOP. be- exposed to the atmosphere: evaporation
Will take place at the upper surface of the column
new portion of water will be drawn I'D To sup-
70 ply the loss; and, if this process he continued
any material which may be dissolved i'm the
o. waier or mechanically mixed with it, will he
? found deposited at the upper Orifce of the tube
= or AT the point of evaporation
V'islf, however. the lower portion Of the tube he
mot furnished with supply of waite. the evapo-
PATTON al the top Will not take place and the dc DO
- sitiOn Of foreign matter will not be exhibited
even though the tube itself NAV be filled with
yater iniPTegnated with impurities The pores
q OF he stones. 50 long the blocks remain in the
yard, are IN the condition of the tube supplied
a its lower end with water. and consequently no
current takes place through them and the amount
\ OF evaporation Is comparatively small; but when
the same blocks are placed in the wall of the
sbailding, the absorbed wafer from the mortar at
the interior surface gives the supply of the liquid
3 necessary to carry the colorin@ materials to the
tesseTioF surface. and depositi. the outer orces
D Of the pores.
The cause Of the phenomenon being known. 4
remedy WAS readily suggested. which consisted
IN covering the surface of the be- embedded
IN mortar with coating of aSphatum. This
remedy has apparently proved successful The
di>coloTation is gradually disappearing and I'M
tine viii probably be entirely impercepIiblc
Tins mafbl with many other specimens, was
suhinttcd To the frczing process fiftY tines in
succession. 10 generally remained in the frcfZ-
Ing mixture for twenty -four hours but sometimes
was frozen twice in the same day. The quantity
Of material lost was W3l5 parts Of an ounce ON
this data Captain Mei9s Las founded an interest
ing calculation which consists in determining
the depth tn which the eNfOIidtiOn extended be-
low The surface IL The effect of lis having been
4 Oxen fifty times lie found this br very neatly
the ten thOUsandth part of an inch. Now If we
allow the Alterations of freezing and thawfng in
wear on an average To be fiftv times each which
in this latitude. wOTd he liberal one. il would
require ten thousand for the surface of The.
marble to be exfOliated to the depth of one inch
This fact may be interesting to the geulogist :; 5
we'll ds the builder
HOSTILE MEEIISG PKEvENTED.-I.a>t night
information was given To Capt. Mills, of the Aux
ilaTy Guard, that arrangements making for
duel between Lieut.. 4 ROney, T.. - y. and
Lieut. HarIell. Of the retired list. l.. = " He
Immediately called Oh Justice Dom. and request
ed warrants TO be issued To- Police Officers Cooper
and Tanning, who, with the Justice, arrested
both the parties They T0gUIFpl % civ S.
Curity In SjUOedch that they viii not depa this
District within months for the pUIDO e Of Hyht-
ing duel. The duel. IL Is said, To- have taken
place az early hour this morning. either at l.
yer spring or BladenNbuTg and Il coach had been !
already engaged To convey Lieut.. Runcv and his |
friends To- the ground. The prompt action #
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