Pierius, [71].
Polar caps, phenomena of, [37], [41], [61];
key to comprehension of planet, [37];
compared with those of earth, [41], [46];
composition of, [39], [161], [168], [339];
making of new, [94];
position of, [68];
maxima and minima of, [38], [41-44], [47-53], [55-57], [66-68], [162];
fission of, [61].