One August afternoon Susan, arriving home from the office at one o’clock, found Mrs. Carroll waiting to ask her a favor.

“Sue, dear, I’m right in the middle of my baking,” Mrs. Carroll said, when Susan was eating a late lunch from the end of the kitchen table, “and here’s a special delivery letter for Billy, and Billy’s not coming over here to-night!  Phil’s taking Jimmy and Betts to the circus—­they hadn’t been gone five minutes when this thing came!”

“Why a special delivery—­and why here—­and what is it?” asked Susan, wiping buttery fingers carefully before she took the big envelope in her hands.  “It’s from Edward Dean,” she said, examining it with unaffected interest.  “Oh, I know what this is—­it’s about that blue-print business!” Susan finished, enlightened.  “Probably Mr. Dean didn’t have Billy’s new address, but wanted him to have these to work on, on Sunday.”

“It feels as if something bulky was in there,” Mrs. Carroll said.  “I wish we could get him by telephone!  As bad luck would have it, he’s a good deal worried about the situation at the works, and told me he couldn’t possibly leave the men this week.  What are the blue-prints?”

“Why, it’s some little patent of Billy’s,—­a deep-petticoat, double-groove porcelain insulator, if that means anyone to anyone!” laughed Susan.  “He’s been raving about it for weeks!  And he and Mr. Dean have to rush the patent, because they’ve been using these things for some time, and they have to patent them before they’ve been used a year, it seems!”

“I was just thinking, Sue, that, if you didn’t mind crossing to the city with them, you could put on a special-delivery stamp and then Billy would have them to-night.  Otherwise, they won’t leave here until tomorrow morning.”

“Why, of course, that’ll do!” Susan said willingly.  “I can catch the two-ten.  Or better yet, Aunt Jo, I’ll take them right out there and deliver them myself.”

“Oh, dearie, no!  Not if there’s any ugliness among the men, not if they are talking of a strike!” the older woman protested.

“Oh, they’re always striking,” Susan said easily.  “And if I can’t get him to bring me back,” she added, “don’t worry, for I may go stay with Georgie overnight, and come back with Bill in the morning!”

She was not sorry to have an errand on this exquisite afternoon.  The water of the bay was as smooth as blue glass, gulls were flashing and dipping in the steamer’s wake.  Sailboats, waiting for the breeze, drifted idly toward the Golden Gate; there was not a cloud in the blue arch of the sky.  The little McDowell whistled for her dock at Alcatraz.  On the prison island men were breaking stone with a metallic clink—­clink—­clink.

Susan found the ferry-place in San Francisco hot and deserted; the tar pavements were softened under-foot; gongs and bells of cars made a raucous clamor.  She was glad to establish herself on the front seat of a Mission Street car and leave the crowded water-front behind her.