"Come on," whispered Tom to Ned. "They'll get along all right together now."
But Eradicate caught the sound of his young employer's footsteps and called:
"Yo' goin', Massa Tom?"
"Yes, Rad. Is there anything you want?"
"No, Massa Tom. I jest wanted to ast if yo' done 'membered de time mah mule Boomerang got stuck in de road, an' yo' couldn't git past in yo' auto? Does yo' 'member dat?"
"Indeed I do!" laughed Tom, and Eradicate also chuckled at the recollection.
"That laugh will do him more good than medicine," declared the doctor, as he took his leave. "I'll come again, when I can make a more thorough examination," he added.
For Tom the following days, that lengthened into weeks, were anxious ones. There was a constant worry over Eradicate. Then, too, he was having trouble with his latest invention—his aerial fire-fighting apparatus. It was not that Tom was financially dependent on this invention. He was wealthy enough for his needs from other patented inventions he and his father owned.
But Tom Swift was a lad not easily satisfied. Once embarked on an enterprise, whether it was the creation of a gigantic searchlight, an electric rifle, a photo telephone or a war tank, he never rested until he had brought it to a successful consummation.
But there was something about this chemical fire extinguishing mixture that defied the young inventor's best efforts. Mixture after mixture was tried and discarded. Tom wanted something better than the usual carbonate and sulphuric combination, and he was not going to rest until he found it.