noon
Thus it may happen that two rains composed of separate liquids may fall together . There being but little of any other atmosphere , much of it consists of what you might call the vapour of hydrogen , and many of the well-known gases and liquids on earth exist only as liquids and solids ; so that , were there mortal inhabitants on Cassandra , they might build their houses of blocks of oxygen or chlorine , as you do of limestone or marble , and use ice that never melts , in place of glass , for transparence . They would also use mercury for bullets in their rifles , just as inhabitants of the intra-Vulcan planets at the other extreme might , if their bodies consisted of asbestos , or were in any other way non-combustibly constituted , bathe in tin , lead , or even zinc , which ordinarily exist in the liquid state , as water and mercury do on the earth . `` Though Cassandra 's atmosphere , such as it is , is mostly clear , for the evaporation from the rivers and icy mediterraneans is slight , the brightness of even the highest noon is less than an earthly twilight , and the stars never cease to shine . The dark base of the rocky cliffs is washed by the frigid tide , but there is scarcely a sound , for the pebbles can not be moved by the weightless waves , and an occasional murmur is all that is heard . Great rocks of ice reflect the light of the grey moons , and never a leaf falls or a bird sings . With the exception of the mournful ripples , the planet is silent as the grave .