"We can explore it from stem to stern," Rick suggested excitedly.
Scotty joined them and commented, "But not right now. We'll have to go ashore and charge the tanks. There may be time for one more dive this afternoon if we hurry."
"Besides," Hobart Zircon said with a smile, "I'm hungry. As you say, Rick, diving certainly develops the appetite!"
They docked, and Tony and Zircon went off to see about preparing sandwiches. The boys decided that rather than carry the tanks back and forth from the pier to the shed, it would be more sensible to bring their small, portable gas-driven compressor to the pier.
Scotty went after it while Rick tied the tanks to the afterrail of the Water Witch, in position for filling.
A yell from Scotty stopped him. He looked up and saw his friend beckon, and ran down the pier to the house. The scientists joined him and Scotty at the shed where the compressor had been stored.
"We've been sabotaged again," Scotty told them flatly. "There's oil in the compressor!"
"Are you certain?" Zircon pressed close to examine the machine.
"Yes. I stumbled over my own feet and tipped the compressor on its side. And oil ran out through the air fitting. Look!" Scotty held up his hand, and it was smeared with glistening oil.
A cold shiver traced its way down Rick's spine. Oil in a compressor was blown into fine particles, too small to be seen. If they got into an air tank they would be breathed in, leaving a thin coating on a diver's lungs. The result was a condition almost exactly like pneumonia, called "lipoid pneumonia." Their special filter, designed by Zircon, probably would have taken all the oil particles out of the air before it got into the tanks, but that didn't alter the fact that faced them. Someone had deliberately put oil in the compressor. Someone just didn't want them around!