WHEN we saw the smoke signal on Greylock, the first thing we thought of was to signal back. But Skinny said: "Come on. He won't be looking for us here. Bob's Hill is the place. He can see us there." We started on a run across the fields, getting more excited every minute. "I don't see how Bill could lose any camp," exclaimed Benny. "And I don't see what he is doing on Greylock when he started for North Adams," Hank said. "Maybe it isn't Bill, at all," I told them. "I've seen smoke on Greylock more than once." "It's Bill all right," Skinny said. "I can almost hear him. We don't know how he got there, but he's there and he can't get back. Something has happened." "Anyhow, we'll soon find out," we all thought, when we came in sight of the twin stones. "I'll run down home and get a blanket," I told them, "while the rest of you make a fire." Our house is right at the foot of the hill and it didn't take me long. The old horse blanket which we used in signaling was in the woodshed. I only stopped long enough to wet it and call to Ma that Bill was up on Greylock signaling. She was almost as excited as I was. "Hurry!" said she. "Don't wait for me. I'll come as soon as I can." I hadn't thought of waiting for anybody. She grabbed a pair of field glasses off the shelf and rushed after me. I heard her calling to Mrs. Blackinton when she went through the yard and I had to go some to keep ahead. By the time we had climbed the hill, the boys had a big fire going and were piling on green branches and leaves to make it smoke. Then we caught hold of the blanket by the corners, ready to shut off the smoke. "Ask if it's Bill," Skinny told us, watching the two smokes on the mountain. Then we signaled, "Is it you, Bill?" and repeated it. Before we had finished the second time Skinny gave a shout. "It's Bill," said he. "He's signaling." We could see one column of smoke break up into puffs, but couldn't see very plain because the smoke was so thin and far away. "Here, take this glass," said Ma, handing the field glass to Skinny. "Hurrah," he cried, after he had looked through them. "I can see real good." Then he held up one hand and we waited while he called off the letters. "H-E-L-P." That was all. We waited for more but nothing came. Before we had turned to go Ma was halfway down the hill and running to beat the band. I knew that if Bill didn't get help it wouldn't be her fault. "See if you can get hold of Mr. Wilson," she called, as soon as we came in sight. "I'll telephone his house. If you can't get him, get somebody. Your father has gone to hitch up and he will be ready to start in a few minutes." In five minutes it seemed as if the whole town knew about it and were out in front of our house, or else climbing the hill to see the smoke. Mr. Wilson came on a run and was in the wagon before Pa could stop the horse.