The aged scientist used no tools whatever, as we understand the term. His laboratory was a power-house; at his command were the stupendous forces of a battery of planetoid accumulators, and added to these were the fourth-order, ninth-magnitude forces of the disintegrating copper bar. Electricity, protelectricity, and fourth-order rays, under millions upon millions of kilovolts of pressure, leaped to do the bidding of that wonderful brain, stored with the accumulated knowledge of countless thousands of years of scientific research. Watching the ancient physicist work, Seaton compared himself to a schoolboy mixing chemicals indiscriminately and ignorantly, with no knowledge whatever of their properties, occasionally obtaining a reaction by pure chance. Whereas he had worked with intra-atomic energy schoolboy fashion, the master craftsman before him knew every reagent, every reaction, and worked with known and thoroughly familiar agencies to bring about his exactly predetermined ends--just as calmly certain of the results as Seaton himself would have been in his own laboratory, mixing equivalent quantities of solutions of barium chloride and of sulphuric acid to obtain a precipitate of barium sulphate. [Illustration: _Hour after hour Rovol labored on, oblivious to the passage of time in his zeal of accomplishment, the while carefully instructing Seaton, who watched every step with intense interest...._] Hour after hour Rovol labored on, oblivious to the passage of time in his zeal of accomplishment, the while carefully instructing Seaton, who watched every step with intense interest and did everything possible for him to do. Bit by bit a towering structure arose in the middle of the laboratory. A metal foundation supported a massive compound bearing, which in turn carried a tubular network of latticed metal, mounted like an immense telescope. Near the upper, outer end of this openwork tube a group of nine forces held the field of force rigidly in place in its axis; at the lower extremity were mounted seats for two operators and the control panels necessary for the operation of the intricate system of forces and motors which would actuate and control that gigantic projector. Immense hour and declination circles could be read by optical systems from the operators' seats--circles fully forty feet in diameter, graduated with incredible delicacy and accuracy into decimal fractions of seconds of arc, and each driven by variable-speed motors through gear-trains and connections having no backlash whatever. While Rovol was working upon one of the last instruments to be installed upon the controlling panel a mellow note sounded throughout the building, and he immediately ceased his labors and opened the master-switches of his power plants.