"What for?" demanded the face in the plate.
"You-know-who's got ideas," said the grid operator scornfully. "Maybe we've been skimping something. Maybe there's some new specification we didn't know about. Maybe anything! But shift to reserve power."
The face in the screen grumbled. Massy swallowed. It was not a Survey officer's privilege to maintain discipline. But there was no particular virtue in discipline here and now. He watched the current-demand dial. It stood a little above normal day-drain, which was understandable. The outside temperature was down. There was more power needed to keep the dwellings warm, and there was always a lot of power needed in the mine the colony had been formed to exploit. The mine had to be warmed for the men who worked to develop it.
The demand-needle dropped abruptly, and hung steady, and dropped again and again as additional parts of the colony's power-uses were switched to reserve. The needle hit bottom. It stayed there.
Massy had to walk around the standby man to get at the voltmeter. It was built around standard, old-fashioned vacuum tubes—standard for generations, now. Massy patiently hooked it up and warmed the tubes and tested it. He pushed in the contact plugs. He read the no-drain voltage. He licked his lips and made a note. He reversed the leads, so it would read backward. He took another reading. He drew in his breath very quietly.
"Now I want the power turned on in sections," he told the operator. "The mine first, maybe. It doesn't matter. But I want to get voltage-readings at different power take-offs."
The Operator looked pained. He spoke with unnecessary elaboration to the face in the phone-plate, and grudgingly went through with the process by which Massy measured the successive drops in voltage with power drawn from the ionosphere. The current available from a layer of ionized gas is, in effect, the current-flow through a conductor with marked resistance. It is possible to infer a gas's ionization from the current it yields.
The cold-lock door opened. Riki Herndon came in, panting a little.
"There's another message from home," she said sharply. Her voice seemed strained. "They picked up our answering-beam and are giving the information you asked for."
"I'll be along," said Massy. "I just got some information here."
He got into his cold-garments again. He followed her out of the control-hut.
"The figures from home aren't good," said Riki evenly, when mountains visibly rose on every hand around them. "Ken says they're much worse than he thought. The rate of decline in the solar constant's worse than we figured or could believe."
"I see," said Massy, inadequately.
"It's absurd!" said Riki fiercely. "It's monstrous! There've been sun spots and sunspot cycles all along! I learned about them in school! I learned myself about a four-year and a seven-year cycle, and that there were others! They should have known! They should have calculated in advance! Now they talk about sixty-year cycles coming in with a hundred-and-thirty-year cycle to pile up with all the others—But what's the use of scientists if they don't do their work right and twenty million people die because of it?"
Massy did not consider himself a scientist, but he winced. Riki raged as they moved over the slippery ice. Her breath was an intermittent cloud about her shoulders. There was white frost on the front of her cold-garments.
He held out his hand quickly as she slipped, once.
"But they'll beat it!" said Riki in a sort of angry pride. "They're starting to build more landing-grids, back home. Hundreds of them! Not for ships to land by, but to draw power from the ionosphere! They figure that one ship-size grid can keep nearly three square miles of ground warm enough to live on! They'll roof over the streets of cities. Then they'll plant food-crops in the streets and gardens, and do what hydroponic growing they can. They are afraid they can't do it fast enough to save everybody, but they'll try!"
Massy clenched his hands inside their bulky mittens.
"Well?" demanded Riki. "Won't that do the trick?"
Massy said: "No."
"Why not?" she demanded.
"I just took readings on the grid, here. The voltage and the conductivity, of the layer we draw power from, both depend on ionization. When the intensity of sunlight drops, the voltage drops and the conductivity drops, too. It's harder for less power to flow to the area the grid can tap—and the voltage-pressure is lower to drive it."
"Don't say any more!" cried Riki. "Not another word!"
Massy was silent. They went down the last small slope. They passed the opening of the mine—the great drift which bored straight into the mountain. They could look into it. They saw the twin rows of brilliant roof-lights going toward the heart of the stony monster.
They had almost reached the village when Riki said in a stifled voice:
"How bad is it?"
"Very," admitted Massy. "We have here the conditions the home planet will have in two hundred days. Originally we could draw less than a fifth the power they count on from a grid on Lani II."
Riki ground her teeth.
"Go on!" she said challengingly.
"Ionization here is down ten per cent," said Massy. "That means the voltage is down—somewhat more. A great deal more. And the resistance of the layer is greater. Very much greater. When they need power most, on the home planet, they won't draw more from a grid than we do now. It won't be enough."
They reached the village. There were steps to the cold-lock of Herndon's office-hull. They were ice-free, because like the village walk-ways they were warmed to keep frost from depositing on them. Massy made a mental note.
In the cold-lock, the warm air pouring in was almost stifling. Riki said defiantly:
"You might as well tell me now!"
‘We could draw one-fifth as much power, here, as the same-size grid would yield on your home world," he said grimly. "We are drawing—call it sixty per cent of normal. A shade over one-tenth of what they must expect to draw when the real cold hits them. But their estimates are nine times too high." He said heavily, "One grid won't warm three square miles of city. About a third of one is closer. But—"
"That won't be the worst!" said Riki in a choked voice. "Is that right? How much good will a grid do?"
Massy did not answer.
The inner cold-lock door opened. Herndon sat at his desk, even paler than before, listening to the hash of noises that came out of the speaker. He tapped on the desktop, quite unconscious of the action. He looked almost desperately at Massy.
"Did she…tell you?" he asked in a numb voice."They hope to save maybe half the population. All the children, anyhow—"
"They won't," said Riki bitterly.
"Better go transcribe the new stuff that's come in," said her brother dully. "We might as well know what it says."
Riki went out of the office. Massy laboriously shed his cold-garments. He said uncomfortably:
"The rest of the colony doesn't know what's up yet. The operator at the grid didn't, certainly. But they have to know."
"We'll post the message on the bulletin board," said Herndon apathetically. "I wish I could keep it from them. It's not fun to live with. I…might as well not tell them just yet.'
"To the contrary," insisted Massy. "They've got to know right away! You're going to issue orders and they'll need to understand how urgent they are!"
Herndon looked absolutely hopeless.
"What's the good of doing anything?" When Massy frowned, he added as if exhausted: "Seriously, is there any use? You're all right. A Survey ship's due to take you away. It's not coming because they know there's something wrong, but because your job should be finished about now. But it can't do any good! It would be insane for it to land at home. It couldn't carry away more than a few dozen refugees, and there are twenty million people who're going to die. It might offer to take some of us. But…I don't think many of, us would go. I wouldn't. I don't think Riki would."