the same thing occur among the nebulæ? And if such changes were once established, would not an important increase of our knowledge accrue, concerning these objects of which almost nothing was known? It was one of the avowed objects of Sir John Herschel's celebrated journey to the Cape of Good Hope to figure the nebulae of the southern sky, and, while there, the drawing given in Fig. 2 was made, although it was not published until 1847.
Fig. 2.—J. Herschel, 1837.
As we have said, Herschel's paper of 1833 created a wide-spread interest among astronomers, and about 1836 two monographic studies of the Horseshoe Nebula were begun, under circumstances so different as to deserve our attention, Lamont, the accomplished director of the Observatory of Munich, and Mason, an undergraduate of Yale College, commenced observations at about the same time: one being supplied with all the appliances which were known to astronomers,
