"Will meet you at the hotel tonight," Dixie called to Grant, and started across the field toward the tracks.
"Loan me your handkerchief, will you?"
It was a call from Grant, and it caused the farmer to turn from watching the pleasing, trim figure of Dixie Mason making her way across the field. He saw that Grant had already filled his own handkerchief with soil dug out of the field. Grant took the spacious piece of cloth which the farmer handed him wonderingly, and walking nearly a hundred feet from where he had taken his original sample of the soil, he knelt down and with his pocket knife dug up another generous clod and put that in the farmer's handkerchief. Then picking up both handkerchiefs, he turned to the farmer:
"Can you drive me right into town? I have some work to do."
"Sure," answered the farmer, impressed by Grant's manner, and then his curiosity prompted the question, "Have you found gold or oil?"
"Maybe something more valuable than either to the wheat farmer," answered Grant. "I think I have found the cause of the fires in the wheat fields, but will know for a certainty by tonight."
The farmer asked no more questions but hurried away, soon to re-appear on the road near the field at the wheel of a speedy little roadster. On the way into town several more fields which had been shorn of their yield by fire were passed and Grant stopped at each one of them. He walked over their blackened lengths carefully until evidently the thing for which he searched was discovered. Then as before he took a sample of the soil and a second sample many yards distant from the first position. By the time the little roadster drove up in front of the one hotel in the nearest city the pockets of both men were filled with Minnesota soil.
They had already made a stop at a drug store where Grant taxed the stock of the proprietor with the demands he made. He succeeded in getting everything that he wanted, acids, salts and other things of which the farmer had never heard. Once in Grant's room at the hotel, the president of the Criminology Club spread out a large piece of white paper on the floor. On it he marked several circles in parallel rows.
"Empty your right hand pockets on this side, and put the soil from your left hand pockets on this side," he ordered briefly, and then in response to the mute request on the face of the farmer he added, "Yes, stay if you want to," and began emptying his own pockets.
With the soil samples from various fields arranged in neat piles on the white paper Grant set to work on matters which were, for the most part, mysterious to the farmer. A Bunsen burner was connected with the chandelier in the room. Small portions of the soil from each pile were placed in separate test tubes. Then each was heated, mixed with small portions of the matter from the various bottles and packages which had been gotten at the drug store. Each test tube was treated in identically the same way and as he finished with each one Grant entered figures in his note book. He was working on the last tube when a knock came on the door, and in response to Grant's "Come" the door opened and Dixie Mason entered. The little Secret Service operative remained silent while Grant finished the test tube. He jotted some figures in his note book, then snapped it shut, and turned toward her smiling.