It was on this same evening that Superintendent Sutherland was almost rewarded for his vigilance by having something distinctly suspicious to report. As it happened, it proved a disappointing incident, but it gave the superintendent something to think about.

He was going a few stations down the line to investigate a rumour of a suspicious person seen in that neighbourhood. It was a vague and improbable rumour and the superintendent was setting out merely as a matter of form, and to demonstrate his vigilance and almost abnormal sense of duty. Darkness had already fallen for an hour or two when he strode with dignified gait down the platform, exchanging a greeting with an acquaintance or two, till he came to the front carriage of the train. He threw open the door of the rear compartment, saw that it was empty, and was just going to enter when glancing over his shoulder he perceived his own cousin Mr. MacAlister upon the platform. Closing the door, he stepped down again and greeted him.

Mr. MacAlister hailed him with even more than usual friendliness, and after a few polite preliminaries drew him insidiously towards the far side of the platform. An intelligent, inveterate and persevering curiosity was Mr. MacAlister's dominating characteristic, and as soon as he had got his distinguished kinsman out of earshot of the herd, he inquired in a hushed voice:

"And what's doing aboot the murder noo, George?"

The superintendent pursed his lips and shook his head.

"Aye, man, yon's a proper puzzle," said he.

"But you'll have gotten a guid idea whae's din it by noo, George?" said Mr. MacAlister persuasively.

"Weel," admitted the superintendent, "we maybe have our notions, but there's no evidence yet, Robbie; that's the fair truth. As the fiscal says, there's no evidence."

"I'd like fine to hae a crack wi' you aboot it, George," sighed Mr. MacAlister. "I may tell you I've notions of ma own; no bad notions either."

"Well," said the superintendent, moving off, "I'd have enjoyed a crack myself if it wasna that I've got to be off by this train—"

"Man!" cried his kinsman, "I'm for off by her mysel'! Come on, we'll hae our crack yet."

The tickets had already been taken and the doors were closed as the two recrossed the platform.

"This carriage is empty," said the superintendent, and threw open the door of the same compartment he had almost entered before.

But it was not empty now. In one of the further corners sat a man wrapped in a dark coloured ulster. A black felt hat was drawn down over his eyes, and his muffled face was resting on his hand. So much the superintendent saw in the brief moment during which he stood at the open door, and it struck him at once that the man must be suffering from toothache. And then his cousin caught him by the arm and drew him back.

"Here, man, the carriage next door is empty!" cried he, and the superintendent closed the door and followed him.

It was scarcely more than a minute later when the whistle blew and they were off, and Mr. MacAlister took out his pipe and prepared himself to receive official confidences. But the miles went by, and though he plied his questions incessantly and skilfully, no confidences were forthcoming. The superintendent, in fact, had something else to think about. All at once he asked abruptly:

"Robbie, did ye see yon man next door sitting with his face in his hands?"

"Aye," said Mr. MacAlister, "I noticed the man."

"Did ye ken who he was?"

"No," said Mr. MacAlister, "I did not."

"Had ye seen him on the platform?"

"No," said Mr. MacAlister, "I had not."

"I didna see him myself," said the superintendent musingly. "It seems funny-like a man dressed like yon and with his face wrapped up too—and a man forbye that's a stranger to us both, coming along the platform and getting into that carriage, and me not noticing him. I'm not used not to notice people, Robbie."

"It's your business, George," said Mr. MacAlister, and then as he gazed at his cousin's thoughtful face, his own grew suddenly animated.

"You're not thinking he's to dae wi' the murder, are you!" he cried.

"I'm not sure what to think till I've had another look into yon carriage," said the superintendent cautiously.

"We're slowing doon the noo!" cried Mr. MacAlister, "God, George, I'll come and hae a look wi' you!"

The train was hardly in the platform before the superintendent was out, with Mr. MacAlister after him, and the door of the next compartment was open almost as soon as the train was at rest. Never had the superintendent been more vigilant; and never had his honest face looked blanker.

"God! It's empty!" he murmured.

"God save us!" murmured Mr. MacAlister, and then he was visited by an inspiration which struck his relative afterwards as one of the unhappiest he had ever suffered from. "This canna be the richt carriage!" he cried. "Come on, Geordie, let's hae a look in the ithers!"

By the time they had looked into all the compartments of the carriage, the guard was waving his flag and the two men climbed hurriedly in again. The brooding silence of the superintendent infected even Mr. MacAlister, and neither spoke for several minutes. Then the superintendent said bitterly:

"It was you hurrying me off to look in thae other carriages, Robbie!"

"What was?" inquired Mr. MacAlister a little nervously.

"I ought to have stopped and looked under the seats!"

Mr. MacAlister shook his head and declared firmly:

"There was naething under the seats. I could see that fine. And onyhow we can hae a look at the next stop."

"As if he'll be waiting for us, now he kens we're looking for him!"

"But there was naething there!" persisted Mr. MacAlister.

"Then what's come over the man? Here were we sitting next the platform. He can't have got out afore we started, or we'd have seen him. Folks don't disappear into the air! I'll try under the seats, though I doubt the man will have been up and out while we were wasting our time in yon other carriages."

At the next station they searched that mysterious compartment earnestly and thoroughly, but there was not a sign of the muffled stranger, under the seats or anywhere else. Again the superintendent was silent for a space, and then he said confidentially:

"I'm just wondering if it's worth while reporting the thing, Robbie. The fiscal might have a kin' of unpleasant way of looking at it. Besides, there's really naething to report. Anyhow I'll think it over. And that being the case, the less said the better. I can tell ye all that's known about the case, Robbie; knowing that you'll be discreet."

"Oh, you can trust me," said Mr. MacAlister earnestly,—"I'll no breathe a word o' yon man. Weel, now, you were saying you'd tell me the haill story."

By this judicious arrangement Mr. MacAlister got his money's worth of sensational disclosures, and the superintendent was able to use his discretion and think the incident over. He thought over it very hard and finally decided that he was demonstrating his vigilance quite sufficiently without mentioning the trifling mystery of the empty compartment.