“Of course it does in many ways,” agreed Bob. “But the crystal is coming back into favor again for some purposes, and the doctor says it’s surprising what results he can get from it.”
Soon after supper they were at the doctor’s house, and as they were all anxious to see the new set, Doctor Dale showed it to them almost immediately after their arrival.
“You see, boys, this set uses the old reliable galena crystal for detection,” he pointed out. “Not so very long ago people all turned up their noses at the humble crystal detector, but now it is being used more and more—with modifications, of course.”
“Yes, but that’s partly due to the fact that you can get such good artificial crystals now, isn’t it?” asked Bob.
“That has a lot to do with it,” replied the doctor. “The natural crystal was nowhere as good as the manufactured variety.”
“Why is that?” inquired Jimmy.
“Well, you see, galena is really a natural crystalline sulphide of lead. In some mineral veins it is found in perfect cubes. As a rule, though, it occurs in big chunks, and most of the natural crystals are just little bits chipped off. The natural galena crystals, as you boys know, are fine if you can strike a sensitive spot, but sometimes such a spot is rather hard to find. Now, with the artificial crystal almost any spot on it will give a fair result.”
“I read somewhere that that was due to so many of the impurities having been eliminated from the artificial galena,” observed Bob.
“Yes, that’s it,” assented the doctor. “The easiest way to get a good crystal is to melt the natural crystals, and then let them solidify again. Galena melts at about one thousand degrees Fahrenheit, and the melting process seems to get rid of most of the impurities. Some time we can make the experiment, if we all feel inclined that way.”
“That would suit me first rate, for one,” asserted Joe. “I’ve found out that if you want to get a good article, the best thing to do is to make it yourself, if you can.”