As Del Mar whizzed along, he could see one of his men approaching over the road, waving to him.  “Stop!” he ordered his driver.

The man hurried forward.  “I’ve got the signal,” he panted.  “They have seen her car over the hill.”

“Good,” exclaimed Del Mar, pulling a black silk mask over his eyes.  “Now, get off quickly.  We’ve got to catch her.”

They sped away again in a cloud of dust.

But even while Del Mar was speeding toward her, another of his men had discovered her presence, so vigilant were they.

He had been keeping a sharp watch on the road, when he was suddenly all attention.  He saw a car, through the foliage.  Quickly, his rifle went to his shoulder.  Through the sight he could just cover Elaine’s head, for her hat, with a bright red feather in it, showed plainly just over the bushes.

He aimed carefully and fired.

I had been out for a tramp over the hills with no destination in particular.  As I swung along the road, I heard the throbbing of a car coming up the hill, the cut-out open.  I turned, for cars make walking on country roads somewhat hazardous nowadays.

As I did so, some one in the car waved to me.  I looked again.  It was Elaine.

“Where are you going?” she called.

“Where are you going?” I returned, laughing.

“I’ve just had a very queer experience—­found something down on the rocks,” she replied seriously, pointing to the square package on the floor of the car.  “I took it to Lieutenant Woodward and he advised me to take it to Professor Arnold on his yacht.  I think it is a bomb.  I wish you’d go with me.”

Before I could answer, up the hill a rifle shot cracked.  There was a whirr in the air and a bullet sang past us, cutting the red feather off Elaine’s hat.

“Duck!” I cried, jumping into the car, “And drive like the dickens!”

She turned and we fairly ricocheted down that road back again.

Behind us, a man, a stranger whom we did not pause to observe, rushed from the bushes and fired after us again.

Suddenly another rifle shot cracked.  It was from another car that had stealthily sneaked up on us—­coming fast, recklessly.

“There’s her car,” pointed one of the occupants to a man who was masked in black.

“Yes,” he nodded.  “Give her a little more gas!"’

“Crouch down,” I muttered, “as low as you can.”

We did so, racing for life, the more powerful motor behind us overhauling us every instant.

We were coming to a very narrow part of the road where it turned, on one side a sheer hill, on the other a stream several feet down.

If we had an accident, I thought, it might be ticklish for us, supposing the square package really to be a bomb.  What if it should go off?  The idea suggested another, instantly.  The car behind was only a few feet off.

As we reached the narrow road by the stream, I rose up.  As far as I could, back of me, I hurled the infernal machine.  It fell.  We received a shower of dirt and small stones, but the cover of the car protected us.  Where the bomb landed, however, it cut a deep hole in the roadway.