The aegis & intelligencer. [volume] (Bel Air, Md.) 1864-1923, 1883-06-22
miscellaneous.
MACADAM ROADS.
MacRdRm's improvements i'm Road Nj ak
ing.

Macadam' y ImprOvementsi I'm Il Dad M LAX
ing.
From the st. James Gazette.
John Loudon Macadam, according to hi!
own account, came to Scotland from America
| in 1888, when the Scotch turnpike acts hat
| been about twenty years in operation anC
roads were still being made everywhere. He
| got appointed commissioner of roads, ant
| afterwards removed to Bristol, where he OBJ
| tanned similar post and was made magis
trate. Gifted with mania ON the subject
| he began about 1894 to travel over the coun
| try at his own cost and these labors he
continued from Inverness to Lands End fol
| and-twenty years, apparently to search
| for well made road.
Macadam's plan of road making differed
| as much from the old way which he found in
operation as bridge does from ford In.
stead of going deep for "bottoming" he work.
ed solely on the top. Instead of producing
II peaked, rooted-like mass of rough, soft
rubbish, he got a fiat, smooth and solid sur.
face In lieu of . road Al feet through, he
made one of Mt most 10inches in thickness, and
for rocks and powders he substituted stone
broken small. His leading principle was
that road ought to be considered as all ar.
titcial flooring, so strong and even as TO let
the heaviest vehicle pass over il without i'm.
pedment. Then people began to hear with
wonder of roads 30 and 40 feet wide rising 3
inches the centre, and he propounded the
extraordinary heresy that better and more
lasting road could be made over the naked
surface of Il morass than over solid rock
Another of his easy first principles was that
the native soil was more resistant when dry
than when wet, and that as in reality il had
to carry not alone the traffic, but the road
a, . t,,,l,t t, h, E.,,,t 80,
| the greatest resistance; that the best way OF
keeping it dry was To put over it covering
| impervious to lain-the road, in fact-and
| that the thickness of this covering was to be
regulated solely in relation to its impervi.
| business and not at all as to its bearing OF
weights, to which the native soil was quite
| equal. Instead of digging trench, there
| fore, to do away with the surface of the ma
| tive soil, he carefully respected it and raised
| his road sufficiently above it to let the water
run Off lmpermeability he obtained by the
| practical discovery that stones broken small
and shaken and pressed together, rs by the
traffic on road, rapidly settled down face 10
| face and angle to angle, and made as close a
mass as II wall Mankind in general now
| believe that this last is all that Macadam in
vented the rest is forgotten. That import
| ant fraction of his discoveries is what has
given to us the verb to macdamiZe
Surprise followed surprise. Roads which
were mere layers of broken stones, six, four
| and even as little rs three inches in thick
| ness, passed through the worst winters with.
| out breaking up, while, as the coachmen used
| to say, they iran true the wheel ran hard
| upon them, it ran upon the nail" Com.
missioners could not believe their eyes when
| they saw new roads made for much less than
it cost them yearly to repair their old ones
When an old road was given into Macadam's
| charge he often made new one of it for f9s
| mile, while around London the cost of an.
nual repairs had been f470 mile For he
knew that the roads-such had been the
| ignorant waste-generally contained mate.
rails enough for their use for several years il
properly applied Unless the road was hope.
less, he went to work in u practical, cheap
way, first cutting away the "gridron" of ruts
in the centre ITO level with the bottom OF
the furrows,' then picking" the road up ia
depth of four inches, removing all the chalk
clay or mud, breaking the large stones small
and simply putting them back again. and one
of his directions to his workmen was that
nothing is to be laid on the clean stone on
pretence of binding" But too often the road
was so bad, rs ut Endham, that it had tn be
removed to its foundations.
fOI Jut ICpullS vi llc IOhu, WHICH once
made. he always chose wet weather, and
"loosened the hardened surface with pick
before putting on the fresh broken stone
| things familiar to us now but paradOxes
! then to all the confraternities of the roads
| In this way he had the greatest success with
the freestone near Bath, and on Il road out OF
| Bristol towards old Down, where everybody
had always said Il good road never would be
made with the materials available This i'm.
possible road, of II miles, which the post
mastergeneral, as a last resource. was about
to indict, he perfected in two months
in 1916, for f55 mile, Indeed, as to mate
rails, they were to some extent matter OF
indifference to lin, provided they were
stones, and stones only.
Event N the breaking of stones Macadam
made revolution. He saw that able bodied
men standing up with heavy hammers vast
ed the greater portion of their strength He
made his stone-breaker sit, so that all the
force of the blows took direct effect on the
stone and the result was that he found
small hammers did the work perfectly well
and thus was enabled to contine it to old men
past hard labor, women and boys, which re-
| duced the cost of the broken stone by one
/ half The size to which the stone should hf