They kept strict rein on this intoxication, ethereal though it was; for, like all their race, they had severe practical issues before them. Daily each of them returned to the less volatile and less pure air of the lower levels in order to check excess of buoyancy and to reinforce the graver purposes of life by consultation with the elders and wise men. They had in their hands an important phase of the well-being and continuance of their race. They had all the foes of human life, as it existed amongst the Limanorans, to fight off, whether seen or unseen. The tornadoes that swept across these subtropical regions, the climatic strata that drifted from other lands or realms of space, the bacterial swarms bringing plague in their train, the lower-planed human life which might swoop down on their shores from the archipelago around them,--all these had to be watched and directed past Limanora. Any one of these evils might in a few hours or days sweep out the civilisation that had taken long centuries to develop and leave them all their steps to retrace. Eye-tense vigilance was needed to watch for any sign of their approach, and the keenest invention to prevent their advance when observed. I had not long to wait for evidences of the great services the Lilamo did to their country. Thyriel and I were led by our guide into the various divisions of the observatory. We inspected the innumerable testing and controlling machines without fully understanding their intricate and often subtle arrangements. Had we not been acquainted with Rimla and Oomalefa and Oolorefa, we should have been bewildered or even awestruck. As it was we were amazed at the refinement of purpose in the apparatus, approaching almost to human intelligence; but we saw that a mere novice would have deranged most of it, so nice were the adjustments.