“You see to it that we keep going straight north,” advised Grant. “That is one of the most important things of all.”
“That suits me,” said George. “Start your measurements.”
The course led off across the sandy beach towards a little clump of pine trees. Placing the toe of John’s shoe close up against the spot on shark’s rock that was their starting place, Grant began to measure. With a small stick he marked the place to which the heel of the shoe extended and then repeated the operation, using the marker for a starting-point. George kept close watch with his compass to see that the correct direction was being followed.
It was slow work and arduous. Everybody was on his hands and knees keeping careful watch of all the operations. The sun was hot and in some places sharp stones or bits of coral were mixed in with the sand so that more than one of the little party soon had bleeding knees and hands as a result. No one seemed to mind or even to notice these discomforts, however. The task they were engaged in was so interesting and absorbing to them that they paid scant attention to anything else.
“Be sure to keep track of the number of times we have measured, Fred,” reminded Grant. “We don’t want any slip-up, you know.”
“Don’t worry about that,” said Fred confidently. “Every time you shift that shoe I make a mark on this page from George’s diary. When there are five marks made I cross them off.”
“How many so far?” inquired John.
“Seventy,” replied Fred after a rapid calculation. “Fifty more to go.”
“Don’t hurry,” warned Grant. “We want it right, you know.”
“We certainly do,” agreed George. “We don’t want to do all this work for nothing.”