some days I have sat at the window overlooking the street there, and have observed the viewpoints of the passers-by. Would you believe"—his voice lowered—"would you believe that only seven and four-tenths percent are even aware of the existence of van Manderpootz? And doubtless many of the few that are, come from among the students in the neighborhood. I knew that the average level of intelligence was low, but it had not occurred to me that it was as low as that."

"After all," I said consolingly, "you must remember that the achievements of van Manderpootz are such as to attract the attention of the intelligent few rather than of the many."

"A very silly paradox!" he snapped. "On the basis of that theory, since the higher one goes in the scale of intelligence, the fewer individuals one finds, the greatest achievement of all is one that nobody has heard of. By that test you would be greater than van Manderpootz, an obvious reductio ad absurdum."

He glared his reproof that I should even have thought of the point, then something in the outer laboratory caught his ever-observant eye.

"Carter!" he roared. "Is that a synobasical interphasometer in the positronic flow? Fool! What sort of measurements do you expect to make when your measuring instrument itself is part of the experiment? Take it out and start over!"

He rushed away toward the unfortunate technician. I settled idly back in my chair and stared about the small laboratory, whose walls had seen so many marvels. The latest, the attitudinizor, lay carelessly on the table, dropped there by the professor after his analysis of the mass viewpoint of the pedestrians in the street below.

I picked up the device and fell to examining its construction. Of course this was utterly beyond me, for no ordinary engineer can hope to grasp the intricacies of a van Manderpootz concept. So, after a puzzled but admiring survey of its infinitely delicate wires and grids and lenses, I made the obvious move. I put it on.

My first thought was the street, but since the evening was well along, the walk below the window was deserted. Back in my chair again, I sat musing idly when a faint sound that was not the rumbling of the professor's voice attracted my attention. I identified it shortly as the buzzing of a heavy fly, butting its head stupidly against the pane of glass that separated the small laboratory from the large room beyond. I wondered casually what the viewpoint of a fly was like, and ended by flashing the light on the creature.

For some moments I saw nothing other than I had been seeing right along from my own personal point of view, because, as van Manderpootz explained later, the psychons from the miserable brain of a fly are too few to produce any but the vaguest of impressions. But gradually I became aware of a picture, a queer and indescribable scene.

Flies are color-blind. That was my first impression, for the world was a dull panorama of greys and whites and blacks. Flies are extremely nearsighted; when I had finally identified the scene as the interior of the familiar room, I discovered that it seemed enormous to the insect, whose vision did not extend more than six feet, though it did take in almost a complete sphere, so that the creature could see practically in all directions at once. But perhaps the most astonishing thing, though I did not think of it until later, was that the compound eye of the insect, did not convey to it the impression of a vast number of separate pictures, such as the eye produces when a microphotograph is taken through it. The fly sees one picture just as we do; in the same way as our brain rights the upside-down image cast on our retina, the fly's brain reduces the compound image to one. And beyond these impressions were a wild hodge-podge of smell-sensations, and a strange desire to burst through the invisible glass barrier into the brighter light beyond. But I had no time to analyze these sensations, for suddenly there was a flash of something infinitely clearer