The cause of his emotion was an envelope which had just turned up in the pile of mail he was sorting. For several minutes his long, nimble fingers had been going through the heap of letters with such speed and dexterity that it seemed impossible that he could be separating and arranging them in rotation, according to the house numbers on his delivery route. He seemed scarcely to glance at the addresses on the envelopes; it appeared to be a purely mechanical operation.

Although there was nothing about this particular white envelope to make it conspicuous, Owen recognized it as soon as it turned up. With a look of deep disgust on his face he withdrew it from the pile.

“This is the fifth he has sent her in the past week,” he muttered. “I wonder who the fellow is, and what he is to her. I wish I knew.

“But, of course, I wouldn’t do anything like that,” he added hastily, ashamed of the unspoken thought. “It is mighty tough, though, to have to deliver your rival’s letters to the girl you love. To suspect that there is a rival is bad enough; but to have to be the bearer of his confounded letters is certainly rubbing it in.”

Uncle Sam’s men in gray are supposed to be mere automatons when it comes to delivering mail. One of the rules of the department is to the effect that carriers must not indulge in any unnecessary conversation while covering their routes; and, of course, they are not supposed to ask any questions or betray any curiosity concerning the letters they carry.

Owen Sheridan was well up on the rules and regulations, but he vowed, as he stepped out of the office to cover his route, that he was going to find out the significance of that letter before another hour had passed.

For thirty minutes he went briskly from house to house, stuffing mail into letter boxes, ringing each bell, blowing his whistle in every vestibule he visited; then, having finished his row of flat houses and private dwellings on the side street, he swung into the avenue and stopped outside a store, on the window of which was the sign, in gilt lettering: “Walter K. Sammis, Real Estate and Insurance.”

For a second he stood on the sidewalk as though afraid to go in. Then he drew a long breath and entered, a half dozen letters in his hand, among them the envelope which was causing him so much concern.

A young woman who sat at a typewriter behind the[{45}] barrier which divided the office in two, looked up from her machine, and greeted him with a cordial smile.

“Good morning,” she said. “You’re a little late to-day, aren’t you? I’ve been waiting impatiently for you—I mean the mail, for the past ten minutes.”