In a few minutes these pains pass away, the workers crawl down the long ladder of the air-shaft and begin to dig away the sand of the sea-bottom. It is heaped high around the bottom of a four-inch pipe which leads up the air-shaft and reaches out over the sea. A valve in the pipe is opened and the sand and stones are driven upward by the compressed air in the caisson and blown out into the water with tremendous force. As the sand is mined away, the great tower above it slowly sinks downward, while the subterranean toilers grow sallow-faced, yellow-eyed, become half deaf, and lose their appetites.

When Smith's Point Light was within two feet of being deep enough the workmen had a strange and terrible adventure.

Ten men were in the caisson at the time. They noticed that the candles stuck along the wall were burning a lambent green. Black streaks, that widened swiftly, formed along the white-painted walls. One man after another began staggering dizzily, with eyes blinded and a sharp burning in the throat. Orders were instantly given to ascend, and the crew, with the help of ropes, succeeded in escaping. All that night the men lay moaning and sleepless in their bunks. In the morning only a few of them could open their eyes, and all experienced the keenest torture in the presence of light. Bags were fitted over their heads, and they were led out to their meals.

Great Waves Dashed Entirely Over Them, so that They had to Cling for Their Lives to the Air-Pipes.

In erecting the Smith Point lighthouse, after the cylinder was set up, it had to be forced down fifteen and a half feet into the sand. The lives of the men who did this, working in the caisson at the bottom of the sea, were absolutely in the hands of the men who managed the engine and the air-compressor at the surface; and twice these latter were entirely deluged by the sea, but still maintained steam and kept everything running as if no sea was playing over them.

That afternoon Major E. H. Ruffner, of Baltimore, the Government engineer for the district, appeared with two physicians. An examination of the caisson showed that the men had struck a vein of sulphuretted hydrogen gas.

Here was a new difficulty—a difficulty never before encountered in lighthouse construction. For three days the force lay idle. There seemed no way of completing the foundation. On the fourth day, after another flooding of the caisson, Mr. Flaherty called for volunteers to go down the air-shaft, agreeing to accompany them himself—all this in the face of the spectacle of thirty-five men moaning in their bunks, with their eyes burning and blinded and their throats raw. And yet fourteen men stepped forward and offered to "see the work through."

Upon reaching the bottom of the tower they found that the flow of gas was less rapid, and they worked with almost frantic energy, expecting every moment to feel the gas griping in their throats. In half an hour another shift came on, and before night the lighthouse was within an inch or two of its final resting-place.