“We had now arrived on the banks of the salt creek; but as we saw the cliff close by, and knew that we must be near the spring which supplied this little rivulet, we resolved to travel on to the fountain-head. A few hundred yards farther brought us to the spring, and it was well worth travelling a little farther to see.
“Near the bottom of the cliff were several round objects, looking like half globes, or bowls turned upon their mouths. They were of a whitish colour, resembling white quartz rock; and of all sizes, from that of a large baking oven to the size of a wooden dish. In the top of each there was a round cavity—like a little crater of a volcano—and in this the blue water bubbled and boiled as though a hot fire was in the ground underneath them. There were in all nearly twenty of these, but many of them were without the crater-like cavity in the top; and through the latter, of course, no water escaped to the creek. These were old ones, that had ceased to run.
“It was evident that these oven-looking mounds had been formed by the water itself, which had been depositing the sediment that formed them for many, many years. Around some of them there grew beautiful plants and shrubs, whose leaves and flowers hung over, trailing in the water; and from the cliff above long vines crept out, covered with gay scarlet blossoms. Bushes of wild currants grew all around, and the fragrance of their leaves scented the air. It was altogether a sweet, cool spot, and filled us with feelings of enjoyment.
“After we had satisfied our curiosity in examining these objects, we prepared to make our salt. Frank and Harry collected armfuls of dry wood for the fire, while Cudjo erected a crane in his usual fashion. Upon this the kettle was suspended, and filled with crystal water out of one of the natural basins. The fire soon blazed under it, and we had nothing more to do than wait until the evaporation should be completed by boiling.
“For this purpose we chose a spot where the ground was carpeted with a soft green turf; and upon it we all sat down to wait the result.
“I need not say that in this we had a deep interest, amounting, in truth, to anxiety. It might not be salt after all. The water tasted salt—that is true. But so, too, would water impregnated by the sulphate of magnesia or the sulphate of soda. When evaporated we might find one or other of these substances.
“‘What is the sulphate of magnesia, papa?’ inquired Frank.
“‘Perhaps you would know it better by the name of Epsom salts!’ rejoined his mother, with a knowing smile.
“‘Bah!’ returned he, with a grin upon his face, ‘I hope it won’t turn out that. But what sort of thing, then, is the sulphate of soda?’
“‘That is the scientific name for Glauber’s salts.’