Trough for watering engines, [111], [232].
Tunnel of the Alps, the, described, [403];
progress, [404];
ventilation, [405];
gradients, [406];
their effects in working the railway, [417];
time to be occupied in going through, [418].
Tunnels, their antiquity, [358];
under the Euphrates, [359];
at Jerusalem, [360];