fell on a long curve to the plain below. It fell near the purple amoeba which it had battled and a long feeler shot out and grasped it. Straight into the purple mass it was drawn, and vanished into the huge bulk.

Jim started one of the stern motors. In a few seconds we were far from the scene.

"Have you any idea of which direction to go?" he asked. I shook my head.

"Have you a radio beacon?" I asked.

He withered me with a glance.

"We're beyond the heaviside layer," he reminded me.

For a moment I was stunned.

"We can't be very far from the hole," he said consolingly as he fumbled with the controls. "But before we try to find it, we had better disconnect one of the stern motors and rig it as a disintegrating ray so that we will have one bearing in each direction. We may meet more denizens of space who like our looks, and we haven't much ammunition left."

We landed on the plain and in an hour had a second disintegrating ray ready for action. Thus armed, we rose from the blue plain and started at random on our way. For ten minutes we went forward. Then Jim stopped the flyer and turned back. We had gone only a short distance when I called to him to stop.

"What is it?" he demanded as he brought the flyer to a standstill.

"There's another creature ahead of us," I replied. "A red one."

"Red?" he asked excitedly as he joined me. About a mile ahead of us a huge mass hung in the air. It resembled the amoeba which had attacked us, except that the newcomer was red. As we watched, it moved toward us. As it did so its color changed to purple.

"Hurrah!" cried Jim. "Don't you remember, Pete, that the one which captured us and took us out of the hole was red while in the hole and then turned purple? That thing just came out of the hole!"

"Then why can't we see the red beam?" I demanded.

"Because there's no air or anything to reflect it," he replied. "We can't see it until we are right in it."

I devoutly hoped that he was right as he headed the ship toward the waiting monster. As we approached the amoeba came rapidly to meet us and a long feeler shot out. As it did so there was a flash of intense light ahead of us as Jim turned loose the ray, and the feeler disappeared. Another and another met the same fate. Then Jim rotated the ship slightly and let out the full force of the ray toward the monster. A huge hole was torn in it, and as we approached with our ray blazing, the amoeba slowly retreated and our path was open before us. Again there was an instant of intense heat as we passed through the red wall, and we were again in the hole which Jim's lamps had blasted through the layer. Below us still lay the fog which had obscured the earth when we had started on our upward trip.

Down toward the distant earth we dropped. We had gone about thirty miles before we saw on the side of the hole one of the huge amoeba which were so thick above.

"We might stop and pick that fellow off," said Jim, "but, on the whole, I think we'll experiment with him."

He drove the ship nearer and turned it on its axis, holding it in position by one of the auxiliary discharges. A flash came from our forward ray and a portion of the amoeba disappeared. A long arm moved out toward us, but it moved slowly and sluggishly instead of with the lightninglike swiftness which had characterized the movements of the others. Jimmy easily eluded it and dropped the ship a few yards. The creature pursued it, but it moved slowly. For a mile we kept our distance ahead of it, but we had to constantly decrease our speed to keep from leaving it behind. Soon we were almost at a standstill, and Jim reversed our direction and drew nearer. A feeler came slowly and feebly out a few feet toward us and then stopped. We dropped the ship a few feet but the amoeba did not follow. Jim glanced at the altimeter.

"Just as I thought," he exclaimed. "We are about forty-five miles above the earth and already the air is so dense that the thing cannot move lower. They are fashioned for existence in the regions of space and in even the most rarified air they are helpless. There is no chance of one ever reaching the surface of the earth without years of gradual acclimation, and even if it did, it would be practically immobile. In a few years the layer will flow enough to plug the hole I have made, but even so, I'll build a couple of space flyers equipped with disintegrating rays as soon as we get down and station them alongside the hole to wipe out any of that space vermin which tries to come through. Let's go home. We've put in a good day's work."

Hundreds of the purple amoeba have been destroyed by the guarding ships during the past five years. The hole is filling in as Jim predicted, and in another ten years the earth will be as securely walled in as it ever was. But in the mean time, no one knows what unrevealed horrors space holds, and the world will never rest entirely easy until the slow process of time again heals the broken protective layer.