"Oh, yes, Uncle WILLIAM!" said SARAH, pausing to wipe her patient little nose; "Our dear Papa is always so pleasant and polysyllabic on these subjects." Then Uncle WILLIAM regretted that he had paid less attention in his youth to the shilling science primers, but he pulled himself together and determined to do his best. "Certainly, my dear children, nothing could please me more. Now here I have a jug and a glass. You will observe that I pour some water from the jug into the glass. This illustrates one of the properties of water. Can you tell me what I mean?" "Fluidity!" said both the children, with enthusiasm. "Yes, quite so, and--er--er--has a brick fluidity?" "Why, no, Uncle WILLIAM!" "Well--er--_why_ hasn't it?" asked Uncle WILLIAM, with something almost like desperation in his voice. "That, Uncle," said the obedient CHARLIE, "is one of the things which we should like to learn from you to-night." "Yes, we shall come to that; but, in order to make you understand it better, I must carry my experiment a little further. In this decanter I have what is called whiskey. I pour some of it into the water. Now it is more usual to put the whiskey in first, and the water afterwards. Can you tell me why that is so? Think it out for yourselves." And Uncle WILLIAM smiled genially. There was silence for a few moments. Then little SARAH said, timidly: "I think it must be because, when a man wishes to drink, whiskey is the first thing which naturally occurs to his mind. He does not think about water until afterwards." "Quite right. That is the explanation of the scientists. And why do you think I put in the water first and the whiskey afterwards?" "It was," said CHARLIE, brightly, "in order that we might not see so exactly how much whiskey you took." "No, that's quite wrong. I did it out of sheer originality. Now what would happen if I drank this curious mixture?" "You would be breaking the pledge, Uncle WILLIAM," said both children, promptly and heartily. "Wrong again. I should be acting under doctor's orders." "Why hasn't a brick any fluidity?" asked SARAH, patiently. "Don't interrupt, my dear child. We're coming to that. Now, CHARLIE, when you eat or drink anything, where does it go?" "It goes into my little--oh, no, Uncle, I cannot say that word," and CHARLIE, who was of a singularly modest and refined disposition, buried his face in his hands, and blushed deeply. "Admirable!" exclaimed Uncle WILLIAM. "One cannot be too refined. Call it the blank. It goes into your blank. Well, whiskey raises the tone of the blank. Just as, when you screw up the peg of a violin, you raise the tone of the string. By drinking this I raise the tone of my blank." He suited the action to the word. "Now you'll be screwed," said CHARLIE, "like the pegs of the--" "On one glass of weak whiskey-and-water--never!" "But why hasn't a brick any fluidity?" asked SARAH, quite patiently.