“Black’s field notes certainly do look good, sir, for they show that you can get the work through on this division in much less time than you had supposed.” As he turned around to speak, Tom sat where he could easily see the colored field map that Harry had just turned in to the chief. “Hold on, there, Harry,” Tom objected. “You’ve lined in a pretty high hill on Section Nineteen. You’ll have to cut that down a bit.” “The surveyor’s field notes call for that hill,” Hazelton retorted. “But, as it happens,” objected Tom, “I’m just working out the profile drawing of Section Nineteen from Black’s notes. See here-----” Tom rested a pencil point on a portion of the hill depicted on Hazelton’s map. “You’ve drawn that pretty steep. Now, as you’ll see by Black’s notes, the upgrade at that point is only a three per cent. grade.” “Humph! It’s all of an eight per cent. grade,” grunted Hazelton. “See, here are the surveyor’s field notes.” “Three per cent. grade,” insisted Tom, holding forward Black’s leveling notes. “There’s a difference there, then, that must be reconciled,” broke in Mr. Thurston, rising, a look of annoyance on his face. “We can’t have any such disagreement as that between the field map and the profile sheet. Let us find out, at once, where the trouble lies.” Yet the more the three pondered over the matter the greater became the puzzle. The notes of the surveyor, Matt Rice, and of the leveler, ’Gene Black, were at utter variance. “We must get hold of these men as soon as they come in tonight,” exclaimed Mr. Thurston, much disturbed. “We must find out just which one is at fault.” “Rice is a very reliable man, sir,” spoke up Tom. “Yes; but Blaisdell reports that Black thoroughly understands his work, too,” grumbled the chief. “We must settle this tonight.” “May I make a suggestion, sir?” asked Tom. “Certainly. Go ahead.” “There is no use, sir, in my going ahead with this profile drawing, if there’s a chance that the sights turned in by Black are wrong. Until we know, my time at this drawing board may all be wasted. Trotter, one of the rodmen, is in camp today. I might take him, and a level along, and go over the foresights and backsights myself. All of the stakes will be in place. In two hours I ought to have a very good set of leveling notes. Then I can bring them back and compare them with Black’s sights.” “Can you run a level well?” inquired Mr. Thurston. “Of course I can, sir. It’s simple enough work, and I’ve done a good bit of it in the east.” “Go along, then, and see if you can throw any light on this,” sighed the disturbed chief. “Reade really ought to have two rodmen,” broke in Harry eagerly. “May I go along, sir, to serve as the other rodman?” “Run along,” assented Mr. Thurston. “Remember, boys, I can’t go any further until this tangle is settled. Come back as speedily as you can.”