is that Eros has a form not unlike that of a dumb-bell, or hour-glass,
turning rapidly end over end so that the area of illuminated surface
presented to our eyes continually changes, reaching at certain times a
minimum when the amount of light that it reflects toward the earth is
reduced to a quarter of its maximum value. Various other bizarre
shapes have been ascribed to Eros, such, for instance, as that of a
flat stone revolving about one of its longer axes, so that sometimes
we see its face and sometimes its edge.

All of these explanations proceed upon the assumption that Eros cannot
have a simple globular figure like that of a typical planet, a figure
which is prescribed by the law of gravitation, but that its shape is
what may be called accidental; in a word, it is a fragment, for it
seems impossible to believe that a body formed in interplanetary
space, either through nebular condensation or through the aggregation
of particles drawn together by their mutual attractions, should not be
practically spherical in shape. Nor is Eros the only asteroid that
gives evidence by variations of brilliancy that there is something
abnormal in its constitution; several others present the same
phenomenon in varying degrees. Even Vesta was regarded by Olbers as
sufficiently variable in its light to warrant the conclusion that it
was an angular mass instead of a globe. Some of the smaller ones show
very notable variations, and all in short periods, of three or four
hours, suggesting that in turning about one of their axes they present
a surface of variable extent toward the sun and the earth.

The theory which some have preferred -- that the variability of light
is due to the differences of reflective power on different parts of
the surface -- would, if accepted, be hardly less suggestive of the
origin of these little bodies by the breaking up of a larger one,