Victor Appleton, Tom Swift and His Giant Telescope… (1939)
“ Tom managed to struggle to his feet. "I remember now! Some kind of gas must have been used on me. But I must see to the office. Maybe I've been robbed."Leaning heavily on the giant's arm, Tom walked as fast as he could into the laboratory. At first glance everything seemed to be in order, and to his relief he found the vault was locked.The young inventor did not know that a key was missing from his ring, nor, as he twirled the dial of the combination-lock, did he realize that a slender lever had been severed from below, thus rendering useless the intricate mechanism. ”
