The Ghost at Skeleton Rock by Franklin W. Dixon

them.
    â€œI’ll read off the extra words included on Chet’s sheet that are different, Frank, and you write them down,” Joe suggested.
    â€œOkay, shoot!”
    Frank wrote the words in a column with the translation opposite each one:
    â€œWhat is it—a code?” asked Tony.
    â€œPerhaps,” said Frank. After a couple of minutes of trying various combinations, he added, “I can’t make any sense out of them.”
    â€œLet’s try the first letters of each Spanish word reading down,” suggested Joe. “C,a,b,e,z,o, n,a,n—”
    â€œThe first word, Cuerpo,” said Tony, “and the last word, Número, both have capital letters. Maybe that means the N should be separated from the rest.”
    Frank wrote it down this way:
    CABEZONA N
    â€œI believe you’re right,” he commented, and consulted a Spanish dictionary. He read aloud:
    â€œâ€˜Cabezon, na, adj. big-headed; stubborn; n. collar of a shirt; opening in a garment for the passage of the head; noseband (for horses ) .’ ”
    â€œDoesn’t make sense to me,” said Frank, “unless the code refers to the Hugo dummy’s big head.”
    â€œThat’s it!” Joe exclaimed. “The instructions might point out that the diamonds were secreted in the dummy’s head! And the N could stand for north, which is the position the dummy’s eyes are located on its face.”
    Excited, the boys warmed up their short-wave radio and beamed out a call over the Hardys’ special frequency. After several minutes Mr. Hardy answered.
    â€œFenton to Bayport. Can you read me?”
    â€œSure can, Dad!” Joe replied into the mike. “We have some important news for you!”
    â€œBetter not tell it now,” Mr. Hardy warned hastily. “Someone may be listening!”
    â€œThen tell us where to reach you and we’ll send it in code by airmail,” Joe told his father.
    â€œI have a better idea, son. Suppose you and Frank fly down here to Puerto Rico and join me. I can use your help. Call Jack Wayne right away and make the arrangements.”
    Chet and Tony had listened to the invitation with envy. “Ask your dad if he can use us,” said Chet. “We could be a big help!”
    â€œIt sure would be a lot of fun,” Joe agreed.
    â€œIt’s okay. Bring your pals along.” Mr. Hardy chuckled, having heard the whole conversation.
    At once Chet and Tony dashed to the hall phone to call their parents. First Chet received permission to take a vacation from his summer work on the farm, then Tony’s father agreed to give him time off.
    The boys were jubilantly talking over their plans when the telephone rang sharply. It was Inspector Moon calling from Eastern City.
    â€œI have some bad news,” he told Joe, who answered. “That prisoner you and your brother captured this morning has just escaped by overpowering a guard.”
    â€œEscaped!” Joe echoed.
    â€œI thought I’d better warn you two,” the officer said.
    â€œThanks, Inspector. We’ll be on our guard.”
    Frank was gravely alarmed when he learned of the escape. “Now we’re in real trouble,” he pointed out. “That man will pass along word to the gang that we have valuable information and they may try to harm us!”
    â€œGood night!” Joe exclaimed. “If they come here while we’re gone, Mother and Aunt Gertrude will be in danger!”
    â€œWe’d better call Sam Radley and ask him to guard the house,” Frank decided.
    Mr. Hardy’s operative readily agreed not only to stand guard himself at night, but to provide around-the-clock protection for the Hardy home. A call to Jack Wayne brought the promise that Mr. Hardy’s new six-seater cabin plane would be fueled and ready for take-off at six the next morning.
    â€œI’ll be there at five to have everything in order,” the pilot