"Magnesia usually is," said Ned.
"Is that magnesia?"
"Yes, in the main. It is mixed a little with other things perhaps, but it is mostly magnesia. That is why I told you to skim it off. We don't want it in the salt."
"But I haven't any salt," said Charley, "I've filled the kettle up every fifteen minutes but no salt has settled yet."
"Your solution isn't saturated yet," said Ned. "This water contains only about two per cent of salt, or possibly in its impure state three per cent. To make one kettleful of salt we must boil away from thirty to fifty kettlefuls of water. The kettle holds two gallons, and so, in order to get a pint of salt we must boil away two or three kettlefuls of water. You have filled it up enough for to-day; now keep it boiling and we'll get a pint or two of salt, before night, and meantime we can pour a little of the boiled-down water on our fish for dinner, for I'm hungry."
"By the way, Ned," said Jack, "what luck have you had?"
"Good. I've brought back a coffee-pot half full, and have made arrangements for more to-morrow."
"Well, I like puzzles and riddles and things of that sort," said Jack, "but I hate to wait for 'our next month's number' for the answer. What is it you've got in the coffee-pot?"
"Bread," answered Ned, "or a substitute for it. I've been gathering the seeds of grasses and weeds."
"Seeds of grasses!" exclaimed Charley; "why, who ever heard of anybody eating grass seeds?"