" 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."

Tom and Harry snatched up their sombreros, hurrying forth. Trotter
was found readily, and was ordered to saddle three ponies. Tom
busied himself in picking out the best leveling instrument in
camp, while Hazelton secured the rods and a chain. Then the party
set forth in Indian file, Tom riding in advance.

A trot of half an hour brought them to Section Nineteen. Here
Tom speedily adjusted his instrument, taking up his post over
the first stake at the bottom of the hill.

Leveling is not difficult work, though it calls for some judgment
and a good deal of care. For instance, when Tom set his telescope
exactly level and took a reading of