"It's evident now," continued Warriner, "that the iron trough at Thaneford's observation point was intended to support a telescope such as this. The instrument is too long to hold steadily in the hand, and it had to be ranged precisely on the two-foot opening of the pridella. It was therefore possible to sit comfortably concealed on Sugar Loaf, and keep accurate tab on whatever was pa.s.sing in Francis Graeme's library; provided, of course, that one of the pridellas was open. Even this wonderful lens could not penetrate stained gla.s.s. It isn't an X-ray apparatus."

"Granting all your premises--why?"

"And that's just what I would like mightily to know," answered Warriner.

"But let's go back to the house; there's something else I want to show you."

We went to the library, and, by way of refreshment after our long walk in the sun, I told Effingham to make us some claret cup. Presently he brought it in, and proceeded to fill a couple of long, Rhinewine gla.s.ses with the beverage. The big cut-gla.s.s pitcher was heavily beaded with cool moisture, and looked irresistibly inviting; the Eighteenth Amendment was unanimously declared unconst.i.tutional, and we drank and drank again. So long as the cellar of "Hildebrand Hundred" continued to function it was still worth while to acquire a thirst.

Warriner took a small object from a cardboard box, and pa.s.sed it over to me. "Remember that?" he asked.

"I suppose it's the same moth coc.o.o.n which we found plastered on the postern-door----"

"And directly on the line between door and casing," interjected Warriner. "Being proof positive that the door could not have been opened for a period considerably antecedent to Graeme's death."

"I presume so."

"Well, I took that coc.o.o.n home, and made some tests. It had been fastened on the door by means of mucilage--common, ordinary mucilage."

I stared at Warriner without speaking. This was indeed confounding.

"To air some of my recently acquired entomological knowledge, I may tell you that the moth caterpillar generally goes underground to enter the pupa stage," continued Warriner. "If the transformation does take place at the surface the coc.o.o.n is sometimes found under a dead leaf or a fallen branch; still more rarely beneath the bark of a tree. It is virtually impossible that it should have been fixed naturally in such an exposed position as the crack of a door.

"Even more significant is the fact that this coc.o.o.n is of a species not indigenous to Maryland; in fact, it doesn't belong to this country at all. Come over here," and he led me to the corner in which stood the gla.s.s cases containing Richard Hildebrand's famous collection of the _lepidoptera_. Warriner pointed out a magnificent specimen of the Great Peac.o.c.k moth of Europe, an entomological aristocrat described by the French naturalist, J. H. Fabre, in one of his fascinating essays. Now all the other specimens of the adult b.u.t.terfly or moth were accompanied by their respective coc.o.o.ns. But below the Great Peac.o.c.k was a vacant s.p.a.ce. Warriner lifted the lid of the case, and extended his hand for the coc.o.o.n that I still held. He fixed it in the empty place. "Certainly it looks as though it belonged there," he said tersely.

Effingham came in to take away the tray of pitcher and gla.s.ses. "Come here, boy," said Warriner with the confident command of the born and bred Southerner, and Effingham was prompt to obey.

"You remember the day Ma.r.s.e Francis died?"

"Ya.s.sah."

"When Miss Eunice sent you up stairs to get the ammonia was she wearing any kind of a wrap?"

"Nossah. Dere was a lil' brack shawl er-hangin' on 'er arm; nuffin else."

Warriner glanced at me. "Keep that in mind," he said quietly. He turned again to Effingham. "Did she ask you for anything?" he continued.

"Nossah."

"I believe you're lying to me. Just think it over ... carefully now."

With the greatest deliberation Warriner took some strands of coa.r.s.e green and yellow worsted from his pocket, and proceeded to tie them into an intricate-appearing knot. Effingham watched him with concentrated and fascinated attention. .

"Well?" said Warriner sharply, and leaned forward with the variegated knot depending from his forefinger. Effingham shivered, and backed away.

"I do 'member one lil' thing," stammered the old man. "Mis' Eunice, she done tole me to-gib 'er----"

"The master-key?"

"Ya.s.sah, dat's ezackly what she done said. She 'splained the doctah might want to go in the liburry befo' I come back."

"Then you did give it to Miss Eunice?"

"She grabbed it fum me, right outen my han', and tole me to git erlong.

An' dat's de whole Gawd's truf, Ma.r.s.e Chalmers."

"All right," nodded Warriner, and Effingham retired with every indication that he was glad to get away.

"Anything is voodoo to one of the old-time darkies," smiled Warriner. "A bit of colored ribbon and two crossed sticks is a good enough 'cunjer'

for almost any emergency."

"I recall your threat at the inquest about the postern-door," I a.s.sented. "It brought home the bacon without delay. All the same, my dear chap, you must admit that these revelations are most disturbing. I don't know----"

"----what to think of Eunice Trevor." Warriner had interrupted to finish out my sentence for me. "But let me sum up my conclusions to date," he continued.

"Miss Trevor was on the library terrace around one o'clock. Presumably she received a signal from the observation point on Sugar Loaf that Francis Graeme was lying dead, and that she might safely enter the room, and abstract the iron despatch-box which was supposed to contain the will disinheriting John Thaneford. She hadn't the nerve to examine the box in the dead man's presence, or she may have been alarmed by some interruption from without--say Effingham's summons to luncheon. The thought occurred to her of blinding her own trail, and so she s.n.a.t.c.hed a coc.o.o.n at random from the case of mounted specimens, daubed it with library gum, and stuck it on the crack of the postern-door, of course from the outside, as she was making her escape by the secret entrance.

Naturally she was not aware that, in her haste, she had dropped one of her roses in the pa.s.sageway.

"In the seclusion of her room she opened and thoroughly searched the box, but found only the original will in which John Thaneford had been named the residuary legatee. The natural explanation would be that Francis Graeme had been prevented from carrying out his intention of making you his heir, and that no later instrument was in existence. In her devotion to John Thaneford's interests, it would now become necessary for her to get the despatch-box back in the library before the tragedy should be discovered and the room carefully examined. She found her opportunity when Doctor Marcy went to meet Betty, leaving Effingham on guard at the library door. You remember the darky telling us that she had a shawl on her arm, an obvious means of concealing such an object as the despatch-box. Then she took the master-key from him----"

"Why did she wait so long?" I interrupted. "She might never have had that chance."

"Well, at the first opening of the library door she may have been too unnerved to risk it. You recall that she fainted at the moment when Marcus, the house-boy, made the discovery of the body.

"In the second place the box is rather bulky, and she would have found great difficulty in placing it in position, under the alert and curious eyes of the servants. Finally, she may have had some thought of re-entering the room by means of the postern-door, which still remained unlocked."

"A desperate _dernier ressort_," I observed. "Somebody would have certainly seen her."

"Granted. Anyway Betty's arrival did give her a chance, and she was quick to take advantage of it.

"Well, that's my case," concluded Warriner. "How does it strike you?"

"It has its weak points."

"Agreed."

"Who unlocked the library door when Doctor Marcy returned with my Cousin Betty?"

"Marcy says it was Effingham. Miss Trevor would want to get the master-key out of her possession the instant that she had accomplished her purpose of replacing the despatch-box. And somehow she managed it, even though Betty and the doctor arrived on the scene a trifle in advance of Effingham's return with the ammonia."

"Very well; we'll drop that issue for the present. a.s.suming that you have fairly reconstructed the action connected with the abstraction of the despatch-box and its return to the room, there still remains the question of how Francis Graeme came to his death. Was it the accident of his falling and striking his head on that same iron box, or was he attacked from behind? Remember that the postern-door was unlocked all the time."

"I don't think it was Eunice Trevor who killed him," returned Warriner.

"Of course, it is conceivable that she entered by the secret way, struck Graeme down, and escaped with the despatch-box; everything else following as before. But, in the first place, she is a woman, and below the normal feminine in the matter of physique. An a.s.sault of this nature is no child's play, even granting the element of complete surprise. Secondly, it is pretty clear that she entered the library in obedience to a signal from John Thaneford. He had been watching the progress of events through his wonderful telephoto lens, and the waving of a handkerchief told her that the way was open."

"How about Thaneford himself?"

"a.s.suming that it was a murder, I still see no ground for trying to fix the guilt on him. He could hardly have approached the library that morning without being seen by Zack and Zeb."

"He might have had an accomplice, or rather a tool. But I suppose that hypothesis is open to the same objection--the continued presence of the two men who were mowing the lawn?"