But hardly had we resumed operation again when what I saw gave me the answer. Bartlett started up his little feed pump, and began vigorously to pump cold water into the hot boiler to bring up the level in the glass. Promptly, as shown by the needle on the gauge, the pressure in the boiler tumbled and the water in the sight glass started to bubble vigorously. And that had been our difficulty. The sudden injection of cold feed water evidently created a vacuum in the steam space. Under the reduced pressure the hot water in the boiler had boiled off so violently that it carried salt spray up with the steam and over into the distiller, where it ruined our make.
Now I had it.
“Enough, brother!” I sang out to Bartlett. “Stop that pump, haul fires and secure everything!”
And from then on, alternating between sweating over that hot boiler and freezing on our enforced trips to the “head,” Bartlett, Lee, and I struggled all through the night. We shifted the location of the feed water line inside the little boiler to a point as far away from the steam space as we could get it, and inserted a constriction in the steam line to the feed pump so that no one could, even by accident, start the pump suddenly or make it stroke at anything more than dead slow speed.
In the early morning, we finished, refilled the boiler, fired up, and again started distilling. When we had to feed the boiler, we fed slowly (which was the only way the pump would now run), and I felt sure from the slight fluctuation of the pressure gauge that I had at last ensured operation steady enough to eliminate priming. And when at noon with the barrel half full of distilled water, Bartlett, Lee, and I, in the front row of a cluster of fellow sufferers, gathered wearily round the surgeon as he poised his silver nitrate solution over the test cup, I felt there was some warrant for the hearty cheer which echoed down the deck when Ambler announced,
“Very pure, chief!”
So ended our struggle to get fresh water. And in a few days our intestinal troubles ended too, a result for which all hands were devoutly thankful. But when I reported our success to the captain, while he was even more laudatory in congratulating me than anyone else had been, still for him there was a fly in the ointment which completely took the edge off his enthusiasm.
“How much coal does that distiller use up, Melville?” he queried.
“About two pounds of coal per gallon of water made, sir,” I answered.
He figured mentally a moment, blinked sadly at me through his glasses, then muttered,