_THE ASTEROIDS, A FAMILY OF DWARF WORLDS_ 129 Only four asteroids large enough to be measured--Remarkable differences in their brightness irrespective of size--Their widely scattered and intermixed orbits--Eccentric orbit of Eros--the nearest celestial body to the earth except the moon--Its existence recorded by photography before it was discovered--Its great and rapid fluctuations in light, and the curious hypotheses based upon them--Is it a fragment of an exploded planet ?--The startling theory of Olbers as to the origin of the asteroids revived--Curious results of the slight force of gravity on an asteroid--An imaginary visit to a world only twelve miles in diameter.