with which they pulled up the upper corner of their sail, after lashing the lower corners to the windlass and fiferail.

It stood the pressure, and the hulk paid slowly off and gathered headway. Boston took the wheel and steadied her at northwest by west-dead before the wind—while the doctor, at his request, brought the open can of soup and lubricated the wheel-screw with the only substitute for oil at their command; for the screw worked hard with the rust of fifty years.

Their improvised sail, pressed steadily on but one side, had held together, but now, with the first flap as the gale caught it from another direction, appeared a rent; with the next flap the rag went to pieces.

"Let her go!" sang out Boston gleefully; "we can steer now. Come here, Doc, and learn to steer."

The doctor came; and when he left that wheel, three days later, he had learned. For the wind had blown a continuous gale the whole of this time, which, with the ugly sea raised as the ship left the lee of the land, necessitated the presence of both men at the helm. Only occasionally was there a lull during which one of them could rush below and return with a can of soup. During one of these lulls Boston had examined the boat, towing half out of water, and concluded that a short painter was best with a water-logged boat, had reinforced it with a few turns of his rope from forward. In the three days they had sighted no craft except such as their own-helpless-hove-to or scudding.

Boston had judged rightly in regard to the wind. It had hauled slowly to the southward, allowing him to make the course he wished-through the Bahama and up the Florida Channel with the wind over the stern. During the day he could guide himself by landmarks, but at night, with a darkened binnacle, he could only

steer blindly on with the wind at his back. The storm centre, at first to the south of Cuba, had made a wide circle, concentric with the curving course of the ship, and when the latter had reached the upper end of the Florida channel, had spurted ahead and whirled out to sea across her bows. It was then that the undiminished gale, blowing nearly west, had caused Boston, in despair, to throw the wheel down and bring the ship into the trough of the sea-to drift. Then the two wet, exhausted, hollow-eyed men slept the sleep that none but sailors and soldiers know; and when they awakened, twelve hours later, stiff and sore, it was to look out on a calm, starlit evening, with an eastern moon silvering the surface of the long, northbound rollers, and showing in sharp relief a dark horizon, on which there was no sign of land or sail.

They satisfied their hunger; then Boston, with a rusty iron pot from the galley, to which he fastened the end of his rope, dipped up some of the water from over the side. It was warm to the touch, and, aware that they were in the Gulf Stream, they crawled under the musty bedding in the cabin berths and slept through the night. In the morning there was no promise of the easterly wind that Boston hoped would come to blow them to port, and they secured their boat reeving off davittackles, and with the plug out, pulling it up, one end at a time, while the water drained out through the hole in the bottom.

"Now, Boston," said the doctor, "here we are, as you say, on the outer edge of the Gulf Stream, drifting out into the broad Atlantic at the rate of four miles an hour. We've got to make the best of it until something comes along; so you hunt through that store-room and see what else there is to eat, and I'll examine the cargo. I want to know where that acid went."

They opened all the hatches, and while Boston descended to the lazarette, the doctor, with his trousers rolled up, climbed down the notched steps in a stanchion. In a short time he came up with a yellow substance in his hand, which he washed thoroughly with fresh water in Boston's improvised draw-bucket, and placed in the sun to dry. Then he returned to the 'tween-deck. After a while, Boston, rumaging the lazarette, heard him calling through the bulkhead, and joined him.

"Look here, Boston," said the doctor; "I've cleared away the muck over this hatch. It's 'corked,' as you sailormen call it. Help me get it up."

They dug the compacted oakum from the seams with their knives, and by iron rings in each corner, now eaten with rust to almost the thinness of wire, they lifted the hatch. Below was a filthy-looking layer of whitish substance, protruding from which were charred, halfburned staves. First they repeated the experiment with the smouldering rag, and finding that it burned, as before, they descended. The whittish substance was hard enough to bear their weight, and they looked around. Overhead, hung to the under side of the deck and extending the length of the hold, were wooden tanks, charred, and in some places burned through.

"She must have been built for a passenger or troop ship," said Boston. "Those tanks would water a regiment.'

"Boston," answered the doctor, irrelevantly, "will you climb up and bring down an oar from the boat? Carry it down-don't throw it, my boy." Boston obliged him, and the doctor, picking his way forward, then aft, struck each tank with the oar. "Empty-all of them," he said.

He dug out with his knife a piece of the whitish sub

stance under foot, and examined it closely in the light from the hatch.

"Boston," he said, impressivly, "this ship was loaded with lime, tallow, and acids-acids above, lime and tallow down here. This stuff is neither; it is lime-soap. And, moreover, it had not been touched by acids." The doctor's ruddy face was ashen.

"Well?" asked Boston.

"Lime soap is formed by the cauticizing action of lime on tallow in the presence of water and heat. It is easy to understand this fire. One of those tanks leaked and dribbled down on the cargo, attacking the lime-which was stowed underneath, as all these staves we see on top are from tallow-kids. The heat generated by the slaking lime set fire to the barrels in contact, which in turn set fire to others, and they burned until the air was exhausted, and then went out. See, they are but partly consumed. There was intense heat in this hold, and expansion of the water in all the tanks. Are tanks at sea filled to the top?"

"Chock full, and a cap screwed down on the upper end of the pipes."

"As I thought. The expanding water burst every tank in the hold, and the cargo was deluged with water, which attacked every lime barrel in the bottom layer, at least. Result-the bursting of those barrels from the ebullition of slaking lime, the melting of the tallow -which could not burn long in the closed-up-spaceand the mixing of it in the interstices of the lime barrels with water and lime-a boiling hot mess. What happens under such conditions?"

"Give it up," said Boston, laconically.

"Lime soap is formed, which rises, and the water beneath is in time all taken up by the lime." "But what of it?" interrupted the other.

"Wait. I see that this hold and the 'tween-deck are lined with wood. Is that customary in iron ships?"

"Not now. It used to be a notion that an iron skin damaged the cargo; so the first iron ships were ceiled with wood."

"Are there any drains in the 'tween-deck to let water out, in case it gets into that deck from above—a sea, for instance?"

"Yes, always; three or four scupper-holes each side amidships. They lead the water into the bilges, where the pumps can reach it."

"I found up there," continued the doctor, "a large piece of wood, badly charred by acid for half its length, charred to a lesser degree for the rest. It was oval in cross section, and the largest end was charred most."

"Scupper plug. I suppose they plugged the 'tweendeck scuppers to keep any water they might ship out of the bilges and away from the lime."

"Yes, and those plugs remained in place for days, if not weeks or months, after the carboys burst, as indicated by the greater charring of the larger end of the plug. I burrowed under the debris, and found the hole which that plug fitted. It was worked loose, or knocked out of the hole by some internal movement of the broken carboys, perhaps. At any rate, it came out, after remaining in place long enough for the acids to become thoroughly mixed and for the hull to cool down. She was in the ice, remember. Boston, the mixed acid went down that hole, or others like it. Where is it now?"

"I suppose," said Boston, thoughtfully, "that it soaked up into the hold, through the skin."

"Exactly. The skin is calked with oakum, is it not?" Boston nodded.

"That oakum would contract with the charring action, as did the oakum in the hatch, and every drop of