With a few deft movements the doctor attached the various parts of the apparatus to their proper places on the baseboard. There was not time that day to put up the aerial, but he gave them practical illustrations of how to use the detector by pressing the point of the wire firmly against the crystal, how to slide the rings back and forth until they found the point of greatest loudness and clearness, and all other points essential to using the set successfully. Not all the boys caught on to all that was involved, but to the majority it was made reasonably clear. To Bob and Joe, who had followed every point of the demonstration with the keenest attention, the operation of the receiving set was made as clear as crystal, and they had no doubt of their ability to construct a set for themselves. Herb's attention had wandered somewhat, because in the back of his mind there still lurked the idea of buying a set ready made. Jimmy had been somewhat distracted by looking about in various parts of the barn to see if he could detect the presence of any "eats," and his ideas were somewhat hazy in consequence.
"Well, boys," at last said the doctor, with a smile, "I guess we'll call it a day. But remember that if at any time you are puzzled and want more information all you have to do is to come and ask me. I'll gladly lay aside my work any time to help you youngsters out."
The boys thoroughly appreciated the doctor's cordiality and the demonstration that he had given them, and most of them took occasion to tell him so as they said good-bye to him and filed out of the extemporized workshop.
"He certainly does make things clear," said Bob enthusiastically, as he and his friends made their way toward their homes.
"Not only that, but he makes you want to do them," said Joe. "After seeing and hearing him this afternoon, I'd ten times rather make a set than buy one."
Jimmy agreed with them, and even Herb seemed ready to reconsider the idea of getting one ready made, though he was not yet quite prepared to surrender.
"All of you come over to my house to-night," said Bob, as they neared their homes. "We haven't got the materials yet, but we can go over again what the doctor told us to-day and make sure that we've got it all straight in our minds. What one forgets, the other may remember. Then when we do get the stuff we can put a little snap and speed into making the set."
"That will be bully," replied Joe, and the others agreed with him. "For my part," Joe continued, "I count every day lost that we have to go without it. I sure am becoming a radio fan."
It turned out that Herb was prevented from coming by unexpected company but the others were there. Their talk that night was animated and enthusiastic, so much so in fact that the time passed more quickly than they imagined, and they were surprised when the clock struck eleven.
"By the way," said Jimmy, as he was preparing to leave with the rest, "I had a run in with Buck Looker when I was coming here to-night, and he said he was going to lay for me and do me up."