Note 4 — Chapter IV

The blast-pipe, also, was one of the most important improvements. Previous to this invention it was necessary to employ bellows to keep up the fire in the boiler, and these were worked by the engine, so that a good deal of power was wasted in order to keep the furnace going, and the greater the speed, the greater the power necessary to work the bellows; moreover, the waste steam ejected from the cylinders was constantly puffing out in the faces of the drivers, so that they could not see clearly before them. This was a great annoyance, which they were most anxious to get rid of, but nobody seemed to know how. At last, either Stephenson, Hackworth, or Booth, or somebody else, whilst driving an engine, and being much annoyed by the blowing in their faces, said, “Confound the steam; let us send it up the chimney.” A pipe was accordingly made, connecting the cylinder with the chimney, so that the discharged steam might be ejected through it into the chimney. When this alteration was made, the engine was again tried, and to their astonishment they not only got rid of the annoyance of the steam, but the bellows were of no use, and the faster the engine went the more vigorous became the fire. Upon thinking over this coolly, the mystery was soon explained, for the hot steam being discharged into the comparatively cold chimney, a vacuum was produced, and the air rushed through the furnace to fill up the vacuum; the faster the engine went the greater the amount of steam sent up the chimney, and the more active the draught through the furnace. The bellows became wholly unnecessary, so much power was saved, and the nuisance of the escaping steam was entirely got rid of. This was really a great step towards in rendering the locomotive more effective; and it is very difficult to ascertain to whom the improvement is justly due.