GRADIENTS of bridges, 23; factors determining, 37-8; of the Fosse Way in Somerset, 38-9; of the roads in the Jura, 40; and of the Vosges, 41; of railroads, 41-2; and the internal-combustion engine, 42; at Lynton and Lynmouth, 42; of the mountain pass, 43-6; of English roads, 89; straightness of Roman roads modified by, 138 GRANITE, use of in road construction, 54-5 GRAVEL, road courses over, 33-4; example in Wey Valley, 34 GRAVESEND, 164 GRAYS, 121 GREAT NORTH ROAD, 50, 163, 191 GUILDFORD, 35, 130 HAMPSHIRE, chalk ridge of, 119; ease of communication through, 130-31 HAMPSHIRE DOWNS, 130 HARDHAM and Stane Street, 139, 168 HASTINGS, 99 HAVRE, 74 HIGHLANDS ROADS COMMISSION and Telford, 187 HILLS, effect of on course of roads, 7-11 HIPPO, 103 HOG’S BACK, the, track over, 35 HOLLAND, roads of, 53-4 HOLMES, RICE, 98 HOLYHEAD ROAD, the, 71-2; and Telford, 186-9; completion of, 192-3 HOUGHTON, 130 HUESCA, bridge near, 24 HUMBER crossed by Roman road, 98, 102; strategical consideration of, 100-01, 104; trackway from Exe to, 117, 125-6, 129 HYDE PARK, 78 ICELAND, 93 ICENI, the, 174 INDUSTRIAL REVOLUTION, the, and the turnpike road, 90 INTERNAL-COMBUSTION ENGINE and gradients, 42; makes a crisis in road building, 91; and the need for new roads, 180, 195-6; danger of crossing roads confined to, and solution of difficulty, 198-9 IRELAND, Chester once the port for, 70 IRON INDUSTRY, the Wealden, 131 ISLAM, Western, influence of drift sand on roads of, 36 ITALY, marshes created by the Road in, 65 JERUSALEM, 70 JUNIPER HILL, near Dorking road, 149 JURA, the, gradients of roads in, 40 KENT, Roman road system in, 98; Roman campaigns in, 102-3; early trackways through, 120-29; approach to London from, 121 LAMBETH, crossing of Thames at, 121; and early trackway, 129 LANCASHIRE, effect of marsh on, 15; plain of, 105, 126; communication of with main trackway, 122 LANDES, the, scarcity of roads in, 53 LEA, RIVER, 122 LEATHERHEAD and Stane Street, 170 LEGISLATION, road, 60-61, 83, 106, 115, 186-8; suggested for arterial roads, 201-5 LEITH HILL and Stane Street, 139, 166, 169 LEWES, lowest old bridge at, 97; and the south coast road, 99 LINCOLN, 35 LINCOLNSHIRE, 125 LITTLEHAMPTON, swing bridge at, 98-9 LIVERPOOL, 129 LIVERPOOL STREET STATION, 68 LOCOMOTIVE (_see_ Railroad) LONDON, crossing of Thames at, 15; plans for rebuilding after Great Fire, 58-9; growth of due to railroads, 67-8; and spread of Christianity, 70; potential between Dover and, 108; centre of a series of trackways, 116-7, 120-2, 129; and Stane Street, 132, 165-6; and Watling Street, 140, 162-4; road entries into, 201; and Chester, 70, 72, 148; lack of potential between, 164