The Press., 1883-11-29
McADiM ROADS.

everywhere. He got appointed com missioner of roads, and afterward removed to Bristol, where he obtained similar post and was made a magistrate. Gifted with mania on the subject, he began about 1794 to travel over the country at his own cost and these labors he contin- ued from Iverness to the Lands End for six-and-twenty years, apparently to search for well-made road.
 McAdams 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 s'bottoming," he worked solely on the top. Instead of producing 8 peaked, roof like mass of rough, soft rubbish, he got flat, smooth and solid surface. In lieu of road four feet and half through, he made one of at most ten inches in thickness l; and for rocks and powders he substituted stone broken small. His leading principal was that road ought to be considered as an artificial flooring, so strong and even d. to let the heaviest vehicle pass over it with out impediment. Then people began to hear with wonder of roads thirty and forty feet wide rising only three inches in the center, and he propounded the extraordi- nary heresy that better and more lasting road could be made over the naked surface of morass than over solid rock. Auoth- CT 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 alone the traffic but the road also, it ought to be kept in condi- tlon of the greatest resistance; that the best way of keeping 1t dry was to put over it covering impervious to rain-the road, ill fact and that the thickness of this cov- ering was to be regulated solely in relation N<>r r%eI T zl III l. itg bearing of weights, to which the native soil was quite equal. Instead of digging trench, therefore, to do away with the sur face of the native soil, he carefully respect ed 1t, and raised the road sufficiently above it to let the water run off. Impermeabil- ity he obtained by the practical discovery that stones broken small and shaken and pressed together, as by the traffic on a road, rapidly settled down face to face and angle to angle, and made as close mass as wall. Mankind in general now be- ieve that this last is all that McAdam in- vented ; the rest is forgotten. That i'm portant factor of his discoveries Is what has given to us the verb to naocodamaize (''To pave a road with small broken stones. "-Skeat), and to the French their nouns nadcGddn1 ('sNom dun pavage in- vente par ..un Anglais. "-Littre), anaca- UtNCUCtITftIyCT. If a man is knocked down by an omnibus in the middle of the boulevard, Parisian bystauder will nowadays say, ''Je Tai vu tomber sur le macadam.'
 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- man used to say, they sran true the wheel ran hard upon them, it ran upon the nail." Commissioners could not be- lieve 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's charge, he often made new one of it for G88 mile, while around London the cost of an- nual repairs had been G470 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 applied. Unless the road was hopeless, he went to work in a practical, cheap way 1; first cutting off the ''gridiron" of ruts in the center s'to lev el with the bottom of the furrows," then picking the road up to 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 pretense of binding." But too often the road was so bad, as at Egham, that it had to be removed to its foundations. 1 For the repairs of his roads, when once made, he always chose wet weather, and ''loosened the hardened surface with a pick" before putting on fresh broken stone : things familiar enough to us now, but par | o1n fn oil ofa,y, ~f the roads. In this way he had the great est success with the freestone near Bath, and on road out of Bristol toward Old Down, where everybody had always said good road never would be made with the materials available. This impossible road of eleven miles miles, which the postmas- | ter-general, as last resource, was about to indict, he perfected ill two months, in 1916, for 955 mile. Indeed, as to mate rials, they were to some extent matter of indifference to him, provided they were stones, and stones only. Flint Essex and Sussex), he said made an excellent road, if only boken properly small limestone (Wilts, Somerset and Gloucester) consol- idates soonest of all, but is not the most lasting the pebbles of Shropshire and Staffordshire were also good, and the beach pebbles of Essex, Kent and Sussex were 
 but the whinstone or granite of the north and of Scotland he pronounced the most durable.
 Even ill the breaking of stones McAdam made revolution. He saw that able bodied men standing up with heavy ham, mers wasted the greater portioa of their strength. He made his stone breakers sit, so that all the force of the blows took di- rect effect on the stone; and the result was that he found small hammers did the work perfectly we'll, and thus was able to confine it to old men past hard labor, wo- mon, and boys, which reduced the cost of the broken stone by one-half. The size to
 which the stone should be broken he de-
 termined in a practical way by the area of contact of an ordinary wheel with smooh
 road. This he found to be about an inch lengthwise, and therefore he laid it down that "a stone which exceeds an inch ill any of its dimensions is..mischievous, <" that is to say, that the wheel in pressing on one
 end of it tends to lift the other end out of
 the road In practice he found it simplest } to fix a weight of six ounces, and his sur veyors carried about scales to test the , largest stones in each heap. He would al- | 1..- L. C., Io