Professor Brierly looked approvingly at the unkempt, red-eyed detective.

"Good work, Mr. Brasher! Splendid! Where did you find it?"

"I'm not as clever as you think, Professor, or I would 'a' had this yesterday. I looked around after you left Miller's Folly. I found tracks of a motorcycle on the ground a short distance away.

We're pretty careful about smuggling any booze around here, you know, Professor, so I asked around, thinking maybe a trooper on our side or mebbe one of the Mounties on this side would have seen or heard a motorcycle.

"A trooper on our side of the line heard a motorcycle about two o'clock yesterday morning. I figgered that if it had b.u.mped off Miller, I wouldn't want to be carting around with me, any longer than I had to, several hundred yards of rope and twine, like you said he had to have. Not with troopers snoopin' around and asking questions mebbe that might be hard to answer.

"I asks myself what would I do with it? I snooped around and about a quarter mile from the Folly there is a gully with weeds growin'

over it so you can't see it unless you know it's there or you fall into it. The motorcycle tracks lead right up to this gully. Mebbe the bird who b.u.mps off Miller rides into it at night. About twenty, thirty yards from the place he rides into it, I find this." He nodded toward the rope which Professor Brierly was carefully examining as he was uncoiling it.

Professor Brierly looked up, a trace of anxiety in his deep eyes.

"Was there water in the gully, Brasher?"

"A little, not to amount to anything."

The anxiety in Professor Brierly's eyes deepened. "Running water, Brasher?"

"Oh, no, not that. Just a little water in the bottom from some rain mebbe, or, mebbe it was seepage."

Professor Brierly's features cleared. There was no hesitation in his manner. He turned briskly to Matthews.

"Did the microscope and slides come, John?" When Matthews answered in the affirmative, he continued:

"A large vessel, John, and some clear cold water."

He turned to the detective.

"Lie down on the hammock there, Brasher, while I am making some tests. I'll wake you when--"

"Do you mind, Professor, if I watch you--if I watch you make your tests?"

"Certainly not, but you will not find it very interesting."

Matthews brought out to the porch an infant's bathtub of enameled metal ware. He poured water in it from the well and asked the old man:

"Won't there be complications, Professor? This water is not distilled and--"

"You will make a microscopic examination of the water, John, and make a careful record, while I wash the rope and twine."

While Matthews went indoors to do his mentor's bidding, the old scientist uncoiled the three sections of rope, twine and fish line. He swirled first one of them violently in the clear water of the bathtub. Then, he siphoned off the water. The water was then subjected to a careful filtering process. The solids resulting from this were subjected to the microscope.

This was done in turn with each section of the coil of rope and twine that Brasher brought. Toward the end of his examination, Professor Brierly had Matthews' help. Jimmy wondered at the smoothness and celerity with which the two men worked. They must have done this many times in the past. There seemed perfect understanding. Without a word being uttered, each man's hands did their appointed task as though one brain dominated them. There was no fumbling, false motions or getting in one another's way.

Each man's movements were carefully checked. The results of the examination of each microscopic slide were carefully noted. They worked with machine-like precision. Jimmy could understand now why Matthews was rapidly attaining a reputation as a scientist second only to his beloved chief. Gone now was the habitual good humored grin with which Matthews treated most things and people. Neither man dominated; both worked as one; there was perfect coordination.

During the tests, Martha came out to call them to lunch; Professor Brierly shook his head impatiently. At the second call he snapped irascibly at the old housekeeper. Turning to the others, he said:

"Go on in and have lunch, all of you; this must be finished." His audience did not budge; their absorption in his task was matched only by his own. Martha shrugged her ample shoulders in resignation and with a snort of disgust left Professor Brierly and his adopted son to their task.

At last it was finished. Professor Brierly spoke to Brasher:

"Bits of brick and mortar on the fish line, twine and rope show that this was in all probability the means used by Miller's murderer. This is probably from the chimney. There is also some roof paint, from the edge of the roof of Miller's Folly."

He looked at the notes he and Matthews had made. He continued: "Mr. Brasher, the rope prior to its use around the chimney of Miller's Folly was for a considerable time at a farm or farmyard, where you will find the following:

"A boxwood hedge, of the species _B. sempervirens_, the common box.

"One or more pear trees.

"You will find these shrubs," handing him a list.

"On that farm there are two horses, a bay and sorrel.

"There is a black and white cow.

"There are some leghorn chickens.

"There is a collie dog."

McCall, Jimmy and Brasher were startled. They stared at the old man in disbelief. McCall said:

"Oh, I say, Professor, see here--" He stopped. He saw Matthews grin and wink at Jimmy. Professor Brierly was oblivious to the interruption. He continued:

"The fish line contains all the characteristics of the rope, but was not at that place for so long a time." He looked once more at his slip of paper.

"I forgot to mention that a stream of water runs through or adjacent to the place where these ropes were kept."

He looked once more at his notes and shook his head.

"The twine," he said slowly, "was also at that place for a considerable length of time. In addition, it appears to have been for some time in a hat factory, where felt hats are made; in a part of a hat factory where a good deal of the fur from the felt hats is in constant motion. I am not familiar with hat factories, but it must be in a branch of the factory, where the hat is worked after it has been dyed."

He caught the detective's look of astonishment.

"Really, Mr. Brasher, there is nothing remarkable about this. Your feat of finding the rope was far more meritorious, both the reasoning and the actual finding of the rope. What John and I did just now was absurdly simple.

"All you need do now, Mr. Brasher, is find a man, probably a left-handed man, who lives on a place such as I described, who owns a motorcycle who cannot account for the time in which we know Mr.

Miller was killed; who either worked in or had access to a hat factory; a man who has a pair of climbing irons and you have the murderer."

"Oh, yeah, is that all?"

Professor Brierly bristled.

"What is there difficult about that? That should be simple. Surely there are not a great many farms or farmyards that comply with all the conditions I enumerated. Surely that should be merely detail, just the work the police ought to be able to do. Ex-Police Commissioner McGuire thinks that too."

He waved his hands with a gesture of finality and Brasher knew that he was dismissed. With a look of awe and reverence he departed, shaking his head wonderingly.