Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1907-08-10

gineer before the next course Is APP
piled. All material used for filling In
terstices in the macadam shall DO
limestone screenings which shall pass
a one-haif (m) inch circular ring.
They shall be FREQ from any injurious
material and shall contain all the dust
of fracture,
Z. Tho roller shall be run along tho
edge OF the stone backward and for
ward several times on each side be-
fore rolling the center. Before put
ting on the filler the bottom course
shall be rolled until the stones do not
creep or wave ahead of the roller. In
no case shall the screenings for filler
be dumped in mass upon the crushed
stone. but they shall be spread uni
fornly over the surface from wagons
or from piles that have been placed
along the curbs. 1t shall then be
swept with rattan or steel brooms and
rolled dry, This process shall be con-
unued until no more will go in dry
when the surface shall be sprinkled
to more effectually I'LL the voids. No
filler shall be left on the surface.
These are among the requirements
that are so openly and frasrantly dis
regarded In all the city street work
now IN progress. AS will be seen, the
specifications are good enough--eN-
celient in fact; but what they are for
no one seems to know, since they have
absolutely no bearing on the nature of
the work. There are frequent viola.
tons of almost every item in No.
and No. Z. Any one can satisfy HIM
self of this fact by a simple inspection
of the work in progress on Second
avenue.
LIMESTONE is BEST.
What can be the purpose Of the
A~n xxh. 1f.tn as s7st q
makers In using the softer and unit
limestone, is variously guessed at. Some
say that an attempt is being made to
discredit macadam in favor OF the
more expensive asphaltum; others, thaS
the purpose is to discredit limerick IN
favor Of quartzite, for in we'll known
claims of this latter material various
city officials are said to be interested.
At this suggestion, the materials used
in other cities have been ascertained.
Limestone has the preference. IL hard,
1t makes the ideal suburban road. Thus
Of the specifications for contract In
Chicago one reads:
CHICAGO USES 1T.
"All trenches shall be filled from the
bottom of the present foundation with
crushed limestone and screenings thor
oughly compacted."
"On the foundation as above pre-
pared shall be spread layer OF
crushed limestone broken to size
which shall pass through ring or "a
inches internal diameter and be heid
on a ring of one inch internal dia-
meter. This layer shall be covered
with fine limestone screenings" etc.
The Chicago specifications go on to
say that on this subgrade, there shall
be spread layer of crushed limestone
broken so as to pass through a ring
", Ia
must then "be covered with fine lime
stone screenings in such quantity as
to completely fill all the intcrstices,
This layer is flooded and rolled, ana
must be not less than seven inches in
depth at the center. Then follows
layer OF limestone four inches deep,
broken so as to pass through ring
2ib inches In diameter, to be covered
with screenings, foeded, and then
rolled. The crushed stone must be
"the best of its kind, dry, clean, uni
form in quality, and as near the cube
form as possible"
GRADES OF ROCK.
AS said before. Salt Lake does not
have the hard, igneous (fire-formed)
rock in sufficient quantity available for
road making. The hard OF igneous
rocks are trap. syenite, granite schist
and gneiss; but the three last named
are often too soft for use, or. as In
the case of the local granite, while
hard enough, yet given to such rapid
disintegration under wear that they are
unfit for road-making, After me isne-
GUS rocks comes limestone. This may
be soft or hard, cementing or non-ce-
menting, ough or brittle, etc. When
suitable, 1t makes a first class road
WE HAVE GOOD MATERIAL.
The Dry canysn rock owned by the
city has combination of the very
best qualities for road-making. IT is,
as compared with most other kinds OF
its own species, that Is. of lime rock,
relatively very hard. tough, and OF high
cemenung power. There can be no
doubt that this city is fortunately stu
AIRED In this respect. 1t has the very
hest of material for average road-maK-
ing, located most conveniently, just
above the thoroughfares, so that 1t
could be delivered on tram cars by the
mere force of gravity to almost any
street in the city.
Compare the advantages of using the
city's hard rock from Dry canyon, with
fine present absurd method OF carting
soft materials for miles up hill from the
ouarries away to the north OF the
Warm Springs, and II is evident tnat
some extraordinary reason Hes pehlna
the action OF the city authori.ios ~
sticking to the private quarries In pref
erence to using the city's own material
LESS VALUABLE KINDS
Next in value comes quartzite, then
sandstone, then slate. then mica schist,
and finally marble. Prof. Shaler con-
siders limestone to be twice as durable
MS sandstone. The latter and slate he
deems worthless for road-making The
softer stones. however. can be used as
the foundation, to be covered on top
with a 4-inch layer of either trap OF
hard limestone nraoadarii.
Chicago makes ssme niacadam roads
from limestone and granite ana some
from limestone only. AS these Iohus
are undoubtedly first class, a study OF
their construction for the purpose OF
coorpnrisDn is valuable in showing the
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