It was in their undergraduate days, however, in the midst of their profoundest plunges into the mysteries of organic chemistry, that Doris Van Benschoten entered into their lives.  Lloyd met her first, but within twenty-four hours Paul saw to it that he also made her acquaintance.  Of course, they fell in love with her, and she became the only thing in life worth living for.  They wooed her with equal ardor and fire, and so intense became their struggle for her that half the student-body took to wagering wildly on the result.  Even “old” Moss, one day, after an astounding demonstration in his private laboratory by Paul, was guilty to the extent of a month’s salary of backing him to become the bridegroom of Doris Van Benschoten.

In the end she solved the problem in her own way, to everybody’s satisfaction except Paul’s and Lloyd’s.  Getting them together, she said that she really could not choose between them because she loved them both equally well; and that, unfortunately, since polyandry was not permitted in the United States she would be compelled to forego the honor and happiness of marrying either of them.  Each blamed the other for this lamentable outcome, and the bitterness between them grew more bitter.

But things came to a head enough.  It was at my home, after they had taken their degrees and dropped out of the world’s sight, that the beginning of the end came to pass.  Both were men of means, with little inclination and no necessity for professional life.  My friendship and their mutual animosity were the two things that linked them in any way together.  While they were very often at my place, they made it a fastidious point to avoid each other on such visits, though it was inevitable, under the circumstances, that they should come upon each other occasionally.

On the day I have in recollection, Paul Tichlorne had been mooning all morning in my study over a current scientific review.  This left me free to my own affairs, and I was out among my roses when Lloyd Inwood arrived.  Clipping and pruning and tacking the climbers on the porch, with my mouth full of nails, and Lloyd following me about and lending a hand now and again, we fell to discussing the mythical race of invisible people, that strange and vagrant people the traditions of which have come down to us.  Lloyd warmed to the talk in his nervous, jerky fashion, and was soon interrogating the physical properties and possibilities of invisibility.  A perfectly black object, he contended, would elude and defy the acutest vision.

“Color is a sensation,” he was saying.  “It has no objective reality.  Without light, we can see neither colors nor objects themselves.  All objects are black in the dark, and in the dark it is impossible to see them.  If no light strikes upon them, then no light is flung back from them to the eye, and so we have no vision-evidence of their being.”

“But we see black objects in daylight,” I objected.