Thus prepared to be warned well in advance of any intrusion, Roger sat wearing the headset as he monitored the volume controls.
Police hid inside and outside of the laboratory.
The safe, bathed in invisible rays, was provided with a new form of “capacity” protection so that anybody or anything touching the metal and standing with feet on the floor, would form a circuit and overload a sensitive and delicately balanced radio tube, that would operate a relay, putting into the circuit a criss-crossed series of small water-hoses, two playing along each side of a square around the safe, not easily observed when inactive.
And in that water would be an electric current strong enough to paralyze and chain, without permanently harming the invader!
He could not avoid it, because the water must fall and no one, even aware what would happen, could dodge or avoid the spray and the stream.
The precious, priceless synthetic camphor secret was protected.
As he sat, knowing that in the dark around him were Doctor Ryder, Potts, and his cousin, Roger felt a little thrill of expectancy and uneasiness.
Had he foreseen the outcome of the ruse, it is a question whether he would have danced for joy or shuddered in terror.
The trap caught something unexpected.