"'Aëro-plane water'" read Margaret. "I wonder what that is."
"I expect it's not so plain as plain water, and not so fizzy as fizzy water," replied Frances. "I think I should like to try it. Suppose you ask for a lemonade and I'll ask for an aëro-plane water, and then we can divide."
"Very well. Then I'll press these two buttons and you press the one marked 'Cookies.'"
They pressed the buttons accordingly, when, almost in no time, it seemed, they heard something go snick, and turning in that direction they saw that a little cupboard door in the wall had flown open. Inside the cupboard was a tray with a plate of cookies upon it and two glasses, one, a big glass of lemonade with two straws in it, and the other, a smaller glass containing what appeared to be plain water with six round, fat bubbles floating about in it. On the edge of this glass, hanging by a little hook, was a pair of small tweezers.
"Why! What are they for?" exclaimed Frances, as she unhooked them and laid them on the tray. "What did they send us tweezers for?"
"I'm sure I don't know," replied her sister. "Perhaps we shall find out presently. Bring the tray over here, Frances, and put it on this little table. Ah! This lemonade is good! What does your aëro-plane water taste like?"
"Why, it doesn't taste like anything," replied Frances, in a tone of some disappointment. "It's just plain water. They must have forgotten the 'aëro' part!"
"Perhaps the bubbles are the 'aëro' part," suggested Margaret.
"Oh, perhaps they are. I'll drink one."
But try as she might, she could not catch one of them. Every time she touched one with her lips it bobbed away—the bubbles were so large and so round and so slippery.