ruddy color of, [148].

Air (see Atmosphere), [86];

necessity of, to life, [166], [167];

as important to astronomical calculations, [7].

Air-waves, [250], [251], [273].

Albedo, low, [162], [167].

Algæ, [349].

Amenthes, hibernation of, [317-324].

Animalcula, in almost boiling geysers, [349].

Aonium Sinus, two doubles suspected in, [242].