The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1885-02-07
Our Olio.
Road Making.

From the st. James Gazette.
John Louden McAdam, according to his
own account, returned to Scotland from
America in 1888, when the Scotch Turn
pike Acts had been about twenty years in
operation and roads were still being made
everywhere. He got appointed commits
sioner of roads, and afterwards removed to
Bristol, where he obtained similar post
and was made magistrate. Gifted with
| mania on the subject, he began about
1894 to travel over the country at his own
cost; and these labors he continued from
Inverness to the Lands End for six-and-
twenty years, for no other purpose, appar-
emily, than to search for well-made road
and the best means of making one. In
this way he spent nineteen hundred and
twenty days, covering thirty thousand
miles, and expended over $4,000. These
facts being well-known in Bristol, he was
in 1916 induced to take the post of general
surveyor Of the Turnpike Trust, which
| then managed all the surrounding roads.
These, to the extent of one hundred and
forty eight miles, were rapidly and ZEN
tirely reformed, and put in the best pos
sible state for use, at an expense consider
ably within the annual revenue of the
Trust which had previously been in
debt about $500 mile. This soon at
tracted general attention. His advice and
assistance were sought in all directions.
Meanwhile he must have had correspon-
dence greater than that Of many minor
government Office, for he explained his
principles and plans to every one with per-
feet candor; and his enthusiasm was such
that his gratuitious services were at the
disposal of all who came to him or sent for
him. What was the talk of the whole
country at length engaged the attention of
Parliament, and a select committee was
appointed in 1919.
McAdam's plan of road-making differed
as much from the old way which he found
in operation as bridge does from ford.
Instead of going deep for ''bottoming," "
he worked solely on the top. Instead of
producing peaked. roof-like mass of soft
rubbish, he got fat, smooth and solid
surface. In lieu of road four feet and a
half through, he made one of at most ten
inches in thickness; and for rocks and boul-
ders he substituted stone broken small
His leading principle was that road ought
to be considered as an artificial flooring, SO
strong and even as to let the heaviest
vehicle pass oyer it without impediment.
Then people began to hear with wonder of
roads thirty and forty feet wide rising only
three inches in the centre; and he pro-
pounded the extraordinary heresy that a
better and more lasting road could be made
over the naked surface of a 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 it had to carry not only
traffic, but the road also, it ought to be
kept in the condition of greatest resistance;
that the best way of keeping it dry was to
put over it covering impervious to rain
the road, in fact; and that the thickness of
this covering was to be regulated solely in
relation to its imperviousness, and not at all
as to its bearing of weights, to which the
native soil was quite equal. Instead of
digging trench, therefore, to do away
with the surface of the native soil, he care
fully respected it, and raised his road suf-
fciently above it to let the water run off.
Impermeability he obtained by the practical
discovery that stones broken small and
shaken and pressed together, as by the
traffic on road, rapidly settled down face
to face and angle to angle, and made as
close mass as wall Mankind in gen.
eral now believe that this last is all that
McAdam invented; the rest is forgotten.
That important fraction of his discoveries
is what has given us the verb to neacada-
mize (''to pave road with small broken
stones -Skeat), and to the French their
nouns-naacaddm (''nom dun payage in
vente par un Apglais "--Litre) macadanat-
sage and the verb naacadamizer.
Surprise followed surprise, Roads which
were mere layers of broken stone, six, four,
and even as little as three inches in thick
ness, passed through the worst winters
without breaking up, while, as the coach
men used to say, they S'ran true; the wheel
ran hard upon them, it ran upon the nail. "
Commissioners could not believe their eyes
when they saw new roads made for much
less than it had cost them yearly to repair
their old ones. When an old road was
given into McAdam' charge he often made
a new one of it for f88 mile, while round
London the cost of annual repairs had been
e470 mile. For he knew that the roads
such had been the ignorant waste
generally contained materials enough for
their use for several years if properly ap-
piled. Unless the road was hopeless, he
went to work in practical, cheap way;
first cutting off the ''gridiron" of ruts in
the centre 'sto level with the bottom of
the burrows" then ''picking" the road up
to depth of four inches; removing all the
chalk, clay or mud; breaking the large
stone 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, as at
Egham, that it had to be removed to its
foundations.
For the repairs of his roads, when once
made, he always chose wet weather, and
"loosened the hardened surface with pick
before putting on the fresh broken stone.
Things familiar enough to us now, but par