produced we must remark that, wherever the moon may happen to be, it bears at all times a long conical shadow projected behind it, sometimes into space, sometimes towards our globe. The cone tapers to a point at a distance which varies somewhat, but is about a quarter of a million miles from the moon. For the production of a total eclipse of the sun it is necessary that the eye which observes should be somewhere within the cone of shadow. Even when the moon does come in between the earth and the sun it will sometimes happen that the shadow-cone is too short to touch the earth, in which case an annular eclipse will result. Sometimes, however, owing to the varying distances of the sun and the moon from the earth this cone does extend far enough to reach the earth, and then observers who happen to occupy any spot in the shadow will have a total eclipse presented to them.
About 1 p.m., Greenwich time, on Sunday, 16th April, the sun was rising in the Pacific Ocean in a state of total eclipse, the moon casting a deep black shadow on the shining waters around. There does not happen to be any island lying near enough to the critical position for its inhabitants to have witnessed this interesting phase of the spectacle: Juan Fernandez was too far to the south and St. Ambrose too far to the north. The region of complete obscuration was at first oval in form, and the shortest diameter extended some ninety miles north and south. The black patch then commenced its great eastward journey, and presently reached land on the coast of South America. The local time was then about half-past seven in the morning at the point of arrival on the coast of Chili, in 30° south latitude. Professor Pickering was among the first of an ardent corps of astronomers ready
