The great bronze lamps were alight, and they cast reflections upon the still damp pavement about them.  To either side, the trees of the Tuileries gardens and of the Cours la Reine and the Champs-Elysees lay in a solid black mass; in the middle, the obelisk rose slender and straight, its pointed top black against the sky; and beneath, the water of the Nereid fountains splashed and gurgled.  Far beyond, the gay lights of the rue Royale shone in a yellow cluster; and beyond these still, the tall columns of the Madeleine ended the long vista.  Pedestrians and cabs crept across that vast space and seemed curiously little, like black insects, and round about it all the eight cities of France sat atop their stone pedestals and looked on.  Ste. Marie gave a little sigh of pleasure, and the two moved forward, bearing to the left, toward the Champs-Elysees.

“And now,” said he, “about these Benhams.  What is the thing I cannot quite recall?  What has happened to them?”

“I suppose,” said the other man, “you mean the disappearance of Miss Benham’s young brother a month ago—­before you returned to Paris.  Yes, that was certainly very odd—­that is, it was either very odd or very commonplace.  And in either case the family is terribly cut up about it.  The boy’s name was Arthur Benham, and he was rather a young fool, but not downright vicious, I should think.  I never knew him at all well, but I know he spent his time chiefly at the Cafe de Paris and at the Olympia and at Longchamps and at Henry’s Bar.  Well, he just disappeared, that is all.  He dropped completely out of sight between two days, and though the family has had a small army of detectives on his trail they’ve not discovered the smallest clew.  It’s deuced odd altogether.  You might think it easy to disappear like that, but it’s not.”

“No—­no,” said Ste. Marie, thoughtfully.  “No, I should fancy not.

“This boy,” he said, after a pause—­“I think I had seen him—­had him pointed out to me—­before I went away.  I think it was at Henry’s Bar, where all the young Americans go to drink strange beverages.  I am quite sure I remember his face.  A weak face, but not quite bad.”

And after another little pause he asked: 

“Was there any reason why he should have gone away—­any quarrel or that sort of thing?”

“Well,” said the other man, “I rather think there was something of the sort.  The boy’s uncle—­Captain Stewart—­middle-aged, rather prim old party—­you’ll have met him, I dare say—­he intimated to me one day that there had been some trivial row.  You see, the lad isn’t of age yet, though he is to be in a few months, and so he has had to live on an allowance doled out by his grandfather, who’s the head of the house.  The boy’s father is dead.  There’s a quaint old beggar, if you like—­the grandfather.  He was rather a swell in the diplomatic, in his day, it seems—­rather an important swell.  Now he’s bedridden.