92 IN STARRY REALMS. 



of glowing cliffs ; if we could extinguish the internal fires, 

 by which at present this mighty cauldron is kept incande- 

 scent, the floor of lava would become congealed, and we 

 should then have a plain surrounded by a ring of cliffs, 

 and offering a resemblance to those objects which are seen 

 by hundreds on the moon. There are other localities in 

 the Sandwich Islands in which the fires have apparently 

 ceased, and where the craters now look as little liable to 

 eruption as are the extinct volcanoes in the moon. The 

 absence of air and water has had a distinctly preservative 

 effect so far as the features of lunar scenery are concerned. 

 As the volcanoes sculptured our satellite into form count- 

 less ages ago, so it has retained that form to the present 

 day. 



If a building were once erected on the moon, it hardly 

 seems conceivable that it should ultimately fall into ruins, 

 if purely volcanic agents are wanting. Without atmo- 

 sphere and without water, what harm can time do to the 

 fabric ? In fact, with the exception of the expansion and 

 the contraction by the alternation of heat and cold, it does 

 not seem that any agent of destruction can exist. We find 

 it difficult to realise the circumstances of an airless globe. 

 Fires could not burn, for there is no air to support the 

 flame ; winds could not blow, for of course wind is only 

 the passage of air from one place to another ; there need 

 be no windows in the building, for there is no air to keep 

 out ; there need be no roof, in so far at least as a roof is 

 required as a protection against rain. Two out of the five 

 organs of sense with which we are endowed operate solely 

 by utilising certain properties which air possesses. Our 

 ears are exquisite contrivances bv which we are enabled to 



