Evening journal., 1890-03-13
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OBSERVATION-DISCLOSURES
uATr or CROss SECTION.

4-lf the stone for the foundation-for
which most anything viii do, and that
kind should be taken which is cheapest
to procure-happens to be got out cheap
est in larger pieces than the above dimen-
sions, it will do no harm. This founda-
tion course is sometimes set so as to pre-
sent an inclination on top, and the cover
then put on Of a uniform thickness over
the whole breadth. This is perhaps best,
but is somewhat more expensive It viii
do, in nearly all cases, 20 set the founda-
ton course on a level, or as near so as
the stones win allow, and then make the
top crowning, by making the covering
say three-quarters Of an inch or an inch
less thick at the edges than in the center.
The stones forming the foundation should
not be set in rows, nor ever laid on their
fiat sides, but set up on edge and made
70 break joints as much as possible; that
Is, set up irregularly. After they are set
up, the points that project above the
general level may be broken off, and the
ipterstices generally filed up with small
stone.
"More or less care and work are neces-
sary In this part OF the operation accord
ing to the importance of the road and
the depth and character Of the material
used for the top covering. To roll the
road at this stage is to be recommended;
afterwards it becomes a requisite. The
point never TO be lost sight of Is that this
foundation course must remain porous,
must be pervious to water, 90 that all
rain water that shall soak through the
top covering will find through ID means
Of escape TO the ground underneath;
thence, according 70 the nature of the
subsoiiJ - IS left either TO soak into the
, RroSnd or must be further led away by
appropriate drains"
Another authority In the same work,
writing upon the top surface for a stone
road, says;
Experience has shown that while six
inches may be a sufficient depth for light
travel, twelve to eighteen inches are
necessary II heavy loads must be carried
at all seasons Of the year. For country
macadam roads the limits would be be-
tween six and twelve inches, according
to the character of the subsoil For the
thorough construction OF macadam roads
the stones are now crushed by machinery
and then rolled with steam road rollers
of ten to fifteen tons weight. The weight
OF the roller per square inch on the bear
ing surface should be equal to the ex
pected weight, per square inch, undel
the wheels Of the heaviest loads.
"Where thorough work Of the bes
character is wanted, engineering skill
and experience cearerequisite but the gen
eral methods may be briefly stated, 81
that wherever bad'slouRhs need filling VI
with stone, the macadam plan may b
followed at least approximately. Th
trench or road bed should be dug out I
the required width and depth, the large
stones should then be selected and hrml
packed together across the foundatio
in irregular courses, in the general forr
Df a street pavement. They should a
rest on their --LATEST or broadest surfaces
and the thin or jagged edges upwarC
The interstices or spaces should be clos
ly filled up with chips and the who
layer be well fammed or rolled into
solid mass.
. "On top Of this place layer Of finel
broken stone of the thickness requisii
TO bring the surface to grade, with
good crown in the center. This shoul
be rolled until the whole mass is firm
h bound together, and then covered wit
q sharp gravel or fine screenings of broke
n stones of sufficient depth to bed and bin
the layer of broken stone. In the futui
maintenanceof Of such road the most in
portant point is 10 prevent the formatic
h Of ruts, by keeping the surface so un
u formly even that there will be no induc
n ment for travel to follow beaten track
The cost of the macadam structure pr
cludes its use on country roads, exec
in occasional bad spots where stone
L necessary"