To many inconveniences produced in the great thoroug,hfarea of this or any other large city, along which heavy stages travel, by reason of the rapid wear of every kind of pavement hitherto adopted, a suspension of the intercourse during the frequent repairs, the dust in summer and the mud in winter, pro duced by a surface of broken stones, and the intolerable noise produced by every species of stone pavement, have lately excited much inquiry as to the possibility of constructing some road having sufficient strength for a traffic so enormous, sufficient durability to prevent the inconvenience of the frequent sus pension of intercourse by the necessity of repairs, and presenting a surface which, while it would be free from the noise of a stone pavement, would not be attended with the inconvenience of dust and mud produced by a surface of broken stone. This problem appears to be in a great de gree solved by the adoption of a pave ment of wood. A short piece of Oxford Street, London, was paved in the begin ning of 1889; and after a successful trial of several months, the same pavement was extended nearly throughout the whole extent of that street ; and tip to the year 1846, this method of pavement was in process of construction in several other thoroughfares of London. The idea of a wooden pavement is not new. In the northern parts of Germany and in Russia such pavements have been long in use ; some of the main streets of Petersburgh and Vienna have long been paved in this manner. A few years ago a series of experiments were made at New York, to determine the best description of paving for a street. One of the methods adopted was a tesselated pavement, form ed of hexagonal blocks of pine wood, measuring 6 inches on each side of their transverse section, and 12 inches in depth. From the manner in which the timber is cut, its fibres are vertical, and therefore the tendency to wear from vertical pres sure is small. The blocks are coated with pitch or tar, forming a smooth upper surface.
Various methods have been proposed for laying the wood pavements of Lon don; but as these methods have been tried and found objectionable, it is un necessary to do more than notice them here. There appears, however, still sufficient to justify a well-grounded ex pectation that wood pavements of some form or other will B0011 supersede all others for great thoroughfares of towns. In constructing roads it is far better to make them as level as possible at first, and rather go round than up the hills. tt is calculated that the power of a horse, 'xi a level, averages 1,000 lbs., at a mod irate pace, and in a rise of 1 in 100 feet he can draw only 900; 1 in 50, 810; 1 in 44, 750; 1 in 40, 720; 1 in 30, 640; 1 in 26, 540; 1 in 24, 500; 1 in 20, 400; 1 in 10, 250. In round numbers, upon a slope of 1 in 44, or 120 feet to the mile, a horse can draw only three-quarters as much as lie can upon a level ; on a slope of 1 in 24, or 220 feet to a mile, he can draw only half as much • and on a slope of 1 in 10, or 528 feet to the mile, only one-quar ter as much. Though a horse on a level is as strong as five men, yet on a steep hill it is less than three ; for three men, carrying each 100 lbs., will ascend faster than a horse with 300 lbs. The
popular theory, that a gentle undulating road is less fatiguing to horses than one which is perfectly level, is pronounced erroneous.
Mr. Bovan lies published results of some experiments on the actual force of draught of carriages upon common roads, all made, or reduced to roads perfectly level or horizontal, to separate the me chanical force due to the inclination of the hill or plane from the force necessary to overcome the friction of the carriage, in its ordinary state, as affected by the condition of the road ; and, by way of rendering them comparable with other experiments, which have been, or may yet be, made on this subject, he consid ered the gross load of the wagon and burden to be divided into 1000 parts.
Loose sandy road, force of draught 204 or Turnpike-road, new gravelled, mean 143 or 1-7th.
Ordinary bye-road, mean 106, nearly 1-91th.
Bard compact loam, mean 53, nearly 1-19th.
Dry hard turf, mean 40 or 1-25th. Turnpike-road, with a little dirt, mean 341 or 1-29th.
Turnpike-road, free from dirt, mean 801 or 1-33d.
From which it appears that five horses will draw with equal ease the same load upon a good hard turnpike-road, as thirty three horses can do upon loose sand ! Or, if we assume the value of draught, upon a well-formed road in good condition, at sixpence per ton per mile, the equivalent price will be e. d.
Upon hard turf 0 74 hard loam 0 9 ordinary bye-road 1 7 " newly gravelled road 2 2 ° loose sandy road 3 1 On hard smooth roads the forces are required to be as the angle of inclination, nearly ; but when the wheels sink, they have to overcome the enlarged angle created by the cavity, in relation to the level ground which follows.
He has published a table, containing the results of experiments made upon the hardness of road materials, or their power of resisting the percussion of a given weight of cast-iron, filling a few inches upon the several specimens broken to the ordinary size, and resting upon stone or iron. Supposing the weather to have no action, the table would express nearly the relative value of the materials, for the purpose of supporting the wear of a road ; and, therefore, those which resist the action of frost and weather, and have the highest numbers, are most val uable.
Sienite 100 White marble 37.31 Cheri pebble, Mid- 34 dlesex Quartz pebble 70 Ferruginous sandstone 20.42 Hurlock from lower chalk 10 Chalk 3 Granite 110 Flint, yellow.. 33'26 Greenstone 110 Sandstone, soft 13-6 'rile fragment 20 Gritstone, near Brixworth 4860 Limestone, near Bradwall 5 Dry clay 12 Flint, black 1110 Portland stone, bard 14 Quartz, white 56 Blue pebble, like Rowley rag 105'110 Coarse limestone, near Stilton 60 Gritstone, near Leeds 100'115 Yorkshire paving-stone 20 Ketton, hard 20 Tetternhoo 4 Chcrt 57 Gray wether, Ilerts and Wilts.., 18 Grit of upper bed, Collymeeton 40 Second bed, ditto 100 Slate at ditto Stockton limestone, alas) 45 Newbold, on Avon, ditto 86 Limestone of Stoke Cruerne 95 Copper slag 244 The steady pressure, without, percus sion, required to crush a of the marble, weighing half an oz., was 100 lbs.; to crush the grey flint, of 1'2 oz. weight, 2000 lbs. ; to crush the rolled I white quartz pebble, of 2 oz. weight, 3400 lbs.