_MERCURY, A WORLD OF TWO FACES AND MANY CONTRASTS_ 18 Grotesqueness of Mercury considered as a world--Its dimensions, mass, and movements--The question of an atmosphere--Mercury's visibility from the earth--Its eccentric orbit, and rapid changes of distance from the sun--Momentous consequences of these peculiarities--A virtual fall of fourteen million miles toward the sun in six weeks--The tremendous heat poured upon Mercury and its great variations--The little planet's singular manner of rotation on its axis--Schiaparelli's astonishing discovery--A day side and a night side--Interesting effects of libration--The heavens as viewed from Mercury--Can it support life?
.