Evening star., 1911-06-03
Member of Hardin Camp.

the trachodon. which Is another one Of
the great lizards. and which was covered
with scales. something like fish. as Is
shown by partial impressions in the
rocks. At other times the restored skele-
tons are not those Of single animal.
Different parts Of similar animals were
found in different localities, and were
pieced together in the museum Some
times. also. there are ribs and vertebra
missing that cannot be recovered. and
these have to be replaced with plaster
casts. But every scrap of geological
testimony that tells how the animal
looked and acted is utilized in mounting
the restored skeleton.
It's footprints in the solidifed sand tell
whether 1t went on two legs or four and
whether it walked, paced or trotted ac-
cording to how the prints were alternat-
ed. Sometimes. as in the case of the
sort Of skin it wore. There Is even an
artist over in New York. Charles r.
knight, who has made speciality of
painting these vanished animals with
their surroundings of prehistoric land
scape. and some OF these pictures are
being used to decorate the walls Of the
new hall.
Take Skeletons Out of Rock.
But to get down to the actual work Of
removing a skeleton from the rock That
is where modern mechanics comes In a
great help. The artist who Is to take the
skeleton out uses a pneumatic chisel for
the most of the work. The cutting edge
of this tool vibrates over an area only a
few sixty-fourths of an inch wide and
strikes about 800 blows a minute. It eats
up the hardest sort of rock almost like a
knife cutting into wood. At the same
time the sculptor has to be microscopical-
ly careful that he does not carve away the
petritied bone with the hard rock matrix
in which it is embedded. When you have
fossil skeleton twenty feet long with
scores of ribs and fine bones. each OF
which have to be taken out without
be carefully repaired. it is no wonder that
single restoration takes months and
months Of time and Sherlock Holmes
study Of all the scraps Of geologic testi-
mony before 1t can be mounted in lifeIike
form. giving an idea Of how the creature
really looked.
Some of the skeletons come in sandstone
and some in the lithograph rock of Ba-
varia, and some are unea arthed in ordina ry
quarries OF building stone. 1t Is hard to
say how deep they have been buried, but
at times they must have been thousands
of feet under ground and were pushed up
in the formation of mountains or un-
of the cliffs where they were hid.
When one side OF bone has been
chiseled out the worst part OF the work
is still to come. The fragile specimen
cannot stand the blows of the pneumatic
chisel without cracking and q bed has te
be made for IT in plaster Of paris and the
first side supported while the second Is
being cut away. After the bones are
taken out Of the rock they have to be re.
stored and repaired where they are in.
jured or missing and then the whole has
to be mounted on an iron frame that
holds all the fragments together.
The man who does the work has to be 9
geologist. stonei 1ason. a machinist and
an artist all combined. 1t is one OF the
most trying jobs In museum building and
one about which the visitors probably
know the least.