Gabrielle and I have just returned from spending the day at Croton Dam. A large party from the prominent families of Chappaqua was organized by Miss Murray, the pretty daughter of one of our neighbors, and at nine o'clock a number of carriages, packed to overflowing with young people and lunch-baskets, and led off by a four-horse wagon, started caravan-wise from the place of rendezvous, Mr. Murray's elegant grounds. The drive was a very pretty one, skirting for some distance the beautiful little lake that supplies the great thirsty city of New York; and the spot chosen for the picnic--shady, terrace-like heights, with a gradual slope to meet the water, and a rough bench here and there--was declared the most suitable place in the world to lay the cloth. One or two members of the party remained behind to unload the carriages, count the broken dishes, and estimate the proportion of contributions--many people fetching salt in abundance but forgetting sugar, whilst others furnished elaborately frosted cakes, but omitted such necessaries as knives and forks. Meantime, we climbed the stone steps leading to the waterworks, and after a glimpse of the seething dark-green water through the heavy iron grating, we hunted up the overseer and asked him to unlock the doors for us, that we might have a nearer view. He assented, and admitted us very obligingly, giving us meantime a graphic description of the yearly journey of the Inspector in a boat down the dark passage to New York, and pointing out the low narrow place of entry from the water-house where they must lie down in the boat. Dinner hour is generally a most interesting moment in a picnic, and this was the time when the young gentlemen showed their gallantry by partaking only of such viands as had come from the baskets of their favorites among the young ladies. A cloth was spread upon the ground; seats were extemporized for the ladies out of carriage cushions, waterproofs and wraps; the knives, forks and plates were dealt out as impartially as possible, and we passed a very merry hour. When the repast was over, the party dispersed--some to play croquet, others to row upon the lake, or to stroll about under the trees; some young ladies produced books and bright bits of fancy-work, while Gabrielle, Arthur and I, with our pretty captain, Miss Murray, and one of her attendant cavaliers, decided to pass away the time by playing a game--no trivial game, however; neither "consequences" nor fortune-telling, but an eminently scientific one entitled "Twenty Questions." For the benefit of the uninitiated I will remark that the oracle chooses a subject (silently), and the others are allowed to put twenty questions to him to enable them to divine it--usually commencing with "Is the object that you have in your mind to be found in the animal, vegetable, or mineral kingdom?"