I will only add that I do wish I had been one of those boys; but--I am glad that I wasn't that hotel-keeper. THE SCHOOL-CHILDREN'S WELCOME. Saturday, December 20, was a splendid holiday for the school-children of Philadelphia. All through the week they had been reading of the receptions given to General Grant in honor of his return from his journey around the world, and now they were to take part in a welcome of their own. There was, in the first place, a grand street procession of boys, to the number of nearly four thousand--quite an army, in fact--who marched in four great divisions, each headed by a band. The boys were well drilled, and stepped gayly to the music, with soldier-like bearing and precision. As the General rode between their lines he was greeted with enthusiastic cheers. No doubt he was as much gratified by this boyish welcome as by the grand military display that attended his entry into the city. After reviewing the lads, General Grant was escorted to the Academy of Music, where almost as many school-girls as there were boys in the procession were assembled to give him a reception of a gentler kind. It must have been a pretty sight--more than three thousand lassies, all in their teens, and all in their best attire. As soon as he appeared, two thousand sweet voices joined in the grand melody of "Hail to the Chief!" which was sung with enthusiasm and fine effect. The General acknowledged the courtesy in a short address. Several other speeches were made, interspersed with patriotic songs. Of all the festivities of the week, the one General Grant will probably remember with most pleasure will be the reception given him by the boys and girls of the public schools. "OLD PROBABILITIES." The next time the Professor came, it was in a dense fog. The morning was so damp and disagreeable that we hardly expected to see him. He did not disappoint us, but seemed to have come almost before the sun was fairly up, it was so dark. "What makes a fog?" asked Gus. "I meant to have talked about something else, Gus," answered the Professor; "but you have chosen a subject for me. It is a very good one, too, and quite suitable to the occasion. Fogs are nothing more nor less than clouds. They usually float aloft, a mile or more, high, but sometimes drift down to the ground and lie all around us. They are so light that they rise and fall from very slight causes, when there is no wind. A brisk breeze soon drives them off." "But what are clouds made of?" inquires May, who has become such a favorite with the Professor that she never hesitates to stop him when she wants anything explained.