"The ancient steam-boiler was equipped with a safety valve to prevent it exploding from too great internal pressure," replied the Chief Scientist. "I advised Nol Kosar to suggest to the Ruler that a vent be bored in the crater of the extinct volcano near Sadri. It is the least fruitful part of Rona, and precautions can be taken to prevent the possible flow of—"
He was cut short by a hideous noise. There was a set of loudspeakers on the etheradio cabinet by the Chief's desk and it was from one of these, colored a significant red for danger, that the harsh wailing was emanating.
The two men exchanged startled looks and their lips moved. Neither could hear what the other was saying, but their words were identical:
"The Emergency Call!"
The Emergency Call had been instituted over two thousand years ago, after a disastrous invasion of the system by beings from some unknown part of space. Installed in all important etheradio stations, it was to be used only in cases of extreme urgency, and at its call all government officials were to drop everything and repair to the nearest etheradio for instructions. In the two thousand years it had been in effect it had sounded only three times, apart from the regular tests: once when a giant meteor had threatened the system with destruction, once when the unknown invaders had attempted a second attack, and once when miners on Mira had drilled into an inner world inhabited by creatures with hypnotic powers that threatened to enslave the planet.
The harsh wailing rose to an earsplitting crescendo, then died away, leaving them listening tensely for the announcement. It came, shorn of the customary formal modes of speech used in official reports:
"Set Gori, Ruler of Rona, here! Three volcanic eruptions on Rona! Violent earthquakes in other regions! Entire planet threatened with destruction! Am evacuating all people we have room for in our space-ships! Send help immediately! Over."
There was hardly a pause before the Chief of the Council of Elders began issuing orders: "Lan Yotar here! Set Gori, concentrate the rest of your people in the nearest cities. Ros Vinla, are you listening?"
"Here!" came the voice of the Commander of the Norgan Spacefleet.