The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1892-11-18
MhcApAM'S SYSTEM.
Principles Upon which He Worked The
Repair of Roads.

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Macadam's plan Of roadmalEing ds.
fcred AZ much from the old way which
he found i'm operation as n bridge doss
from a ford. Instead of going deep FOR
n s'bottoming' he worked solely on the
top. Instead of producing a peaked, |
rooaike mass Of rough. soft rubbish, he |
got a fiat, smooth and solid surface. In
lieu Of a road AZ feet through he made
n Of at most ten inches in thickness, |
and for rocks and powders he substi.
tinted stone broken small. His LEADING
principle was that a road ought to bs
considered as an artificial flooring, 50
strong and even as to let the heayies.
vehicles pass over it without impedi-
ment. Then people began TO hear with
wonder OF roads thirty to forty feet wild,
rising only three inches in the center.
and he ~propounded the extraordinary
heresy that n better and more lasting
road could be made owe the naked sur
face of a morass than ove solid rock.
Another Of his easy first principles
was that the native soil was more resist
ant when dry than when wet, and thatas
a reality. as it had to carrynot alone the
traffic. but the road also, it ought 70 Is
kept in a condition Of the greatest re.
e~istance: that the best way Of keepin,
it dry was to pat over 1t q covering in-
nervous TO rain-the road in fact--ani
that the thickness Of this covering Wa
to be regulated solely in its relation t
its impcrviousness. and NOT at all as .
It's bearing Of weights, to which the IA
tive soil was quite equal. Instead O
digging a trench, therefore, y do ava
with the surface Of the native soil, b
carefully respected it, and raised III
road sufficiently above IL toiet the waite
rrn off. Impermeability he obtained b
the practical discovery that ston'
broken small and shaken nd presse
together, as by the traffic on a roa'
rarielv settled down face 30 face al
anrle with angle. and made az close
mass Is n wall. Mankind nos belle
J that this last is all that Macadam
vented: the res is forgotten.
Surprise followed surprise. Roa
which were mere layers Of broken stor
six. four ard even as little as til
inches in thickness passed through I
", rst winters without breaking Z
' while, as the coachman used 70 ss
they iran true; the wheel ran hard W
them; it ran upon the nail
: For the renairs Of his road when o.
~ made he always chose wet weather 9
- ..loosened the hardened surface vii
a pick before putting en- the first brol
= something's familiar enough tousn
, but paradoxen then TO all the contra
mites of the roads.
la. The size to viii, h the stone shoul'
: broken he determined in a practical
: bv the area of contact OF an ordir
wheel with "A smooth road. Tins
os. found to be about an inch lengthy
~ and therefore he laid 1t down tn
..stonc which exceeds an inch IN ar
its dimensions is mischievous'-th
70 saw. that the wheel in pressing Oh
end of it tends to lift the other en-
a. Of the road. In practice he fonn
. simplest to fix u weight Oh siA on'
10 ard his surveyors carried about =
70 test the largest stones in each !
~ He would allow no large stones eve
the Foundation Of his roads, for Lef
that they constantly worked upwai
the pressure aud vibration OF the IT
ssio The whole road was small broken $
even over swamny ground.-Sou'
Planter.