are curious in the extreme; but before we ask what they are, let us cross the barrier, and see with what tools the weather-students work. The main building is built in the form of a cross, with its chief front to the magnetic north. It is formed of wood, all iron and other metals being carefully excluded; for its purpose is to contain three large magnets, which have to be isolated from all influence likely to interfere with their truthful action. In three arms of the cross these magnets are suspended by bands of unwrought, untwisted silk. In the fourth arm is a sort of double window, filled with apparatus for receiving the electricity collected at the top of the mast which stands close by. Thus, in this wooden shed, we find one portion devoted to; electricity--to the detection and registry of the stray lightning of the atmosphere--and the other three to a set of instruments that feel the influence and register the variations of the magnetic changes in the conditions of the air. "True as the needle to the pole," is the burden of an old song, which now shows how little our forefathers knew about this same needle, which, in truth, has a much steadier character than it deserves. Let all who still have faith in the legend go to the magnet-house, and when they have seen the vagaries there displayed, they will have but a poor idea of Mr. Charles Dibdin's sea-heroes, whose constancy is declared to have been as true as their compasses were to the north. Upon entering the magnet-house, the first object that attracts attention are the jars to which the electricity is brought down. The fluid is collected, as just stated, by a conductor running from the top of the mast outside. In order that not the slightest portion may be lost in its progress down, a lamp is kept constantly burning near the top of the pole, the light of which keeps warm and dry a body of glass that cuts off all communication between the conductor and the machinery which supports it. Another light, for the purpose of collecting the electricity by its flame, is placed above the top of the pole. This light, burning at night, has given rise to many a strange supposition in the neighborhood. It is too high up to be serviceable as a lantern to those below. Besides, who walks in Greenwich Park after the gates are closed? It can light only the birds or the deer. "Then, surely," says another popular legend, "it is to guide the ships on the river, when on their way up at night; a sort of landmark to tell where-abouts the Observatory is when the moon and stars are clouded, and refuse to show where their watchers are."