10

REPORT ON EUROPEAN TUNNELS.

seen; the day was clear and bright. After we had gone through aboutone-third of its length, a locomotive passed us, going down the tunnel,and produced no perceptible smoke. A moment after, an expresspassenger train passed us, going up on the other track. It filled thetunnel with smoke and produced perfect darkness—not only so thatneither end of the tunnel could any longer be seen, but that uponremoving the lights we were carrying, the person w'ho sat at my side,talking with me and touching me, was absolutely invisible; with allthis however, there was nothing in the least troublesome to respira-tion. As we proceeded and successively passed the large shafts, a rayof light appeared directly under them, which a moment after was lostagain in the intense darkness and this continued until we reached theother end of the tunnel, after an interval of fifteen or twenty minutesfrom the passage of the express train. The tunnel is somewhat wet,but not so as to occasion much inconvenience except in a few spots,and at the shafts. At these a considerable quantity of water is con-stantly dripping down, which much annoys the workmen and all whohave charge of the repairs. The ventilation of the tunnel depends agood deal upon the weather. Whenever a strong clear wind is blow-ing, the smoke escapes very quickly; but in foggy weather it is quitetroublesome to the workmen. I could not find however, that itseriously interfered with their work; and indeed Mr. Amor, the in-spector, told me there never was a time when work could not be donethere if required. No artificial means have ever been used to venti-late this tunnel since it was opened for travel; but the passage ofquick trains going down the tunnel, in the ordinary course of the opera-tions of the road, is a powerful agent for this purpose. The grade, ashas been stated, is 1 in 100, or 52.80 per mile. With so steep a grade,the steam, on the descent of the tunnel, is nearly or quite shut off andthe train passes quickly through. The first engine which passed us,moving down, while we were in the tunnel, produced no perceptibleeffect upon the air; but in ascending the tunnel there is a great expen-diture of steam; the trains move slowly and heavy trains are assistedby a second engine. All this of course vitiates the air, as we noticedupon the passage of the express train upwards. The quick passageof a train always produces a current in the direction of its motion, andif made by a train running downward and therefore using but littlesteam, its effect in clearing the tunnel is very marked. This effecthowever, is said to be rather impeded than assisted by the presence ofshafts; and I found that the persons who had charge of this tunneltaking this circumstance into consideration together with the trouble