"All right. Sit here and watch that shed. No matter if it blows away. They were going to tear it down anyway." He placed my chair directly behind the sighted tube.
With an access of eagerness in his countenance, and something of tremor apparent in his clutching fingers, he lifted the bulb, unscrewed its metal cap and worked the tangent screw while watching the vernier intently. He was evidently screwing the basal half closer to the nozzle-bearing upper portion.
From a minute orifice in the nozzle or stem something exuded that appeared first as a tiny, shimmering, sunbright, revolving globule. At that instant he placed the bulb on its base in its niche or groove at the outer or window end of the sighted box. Thus the strange revolving globule was rising directly in the line of sight.
"Watch that shed," Adam ordered hoarsely.
I could not wholly take my eyes off the singular sphere, which resembled nothing that I have elsewhere seen so much as a focus of sun rays from a burning glass. But this intensely bright spot or mass—for it appeared to have substance even as the incandescent carbon of an Edison lamp seems to possess substance exterior to the carbon—rose expanding in an increasing spiral within an iridescent translucent film that clung by a tough stem to the orifice of the nozzle, somewhat as a soap-bubble clings to the pipe whence it is blown. Yet this brilliant, this enlarging, this magic globule was plainly whirling on its perpendicular axis as a waterspout does, and that with speed terrific. The mere friction of its enclosing film on the air stirred such wind in the room as might come from an eighteen-inch electric fan. In shape the infernal thing rapidly became an inverted cone with spiral convolutions. It hummed like a distant, idly-running circular saw, a great top, or the far-off, mysterious forewarning of a typhoon.
"Now!" Adam touched a button on the top of the metal box.
The gleaming, whirling, humming, prismatic spiral was then about eighteen inches high. It vanished without sound or spark, as if the film had been totally destroyed and the contained incandescence quenched on liberation. For one instant I experienced a sense of suffocation, as if all the air had been drawn out of the room. The inner shutters clashed, the holland sunshade clattered, the door behind me snicked open, air from the corridor rushed in.
"See the river!" Adam was exultant, but not too excited to replace the metal cap on the nozzle.
Certainly the Charles River was traversed by a gust that raised white caps instantly. A bulk-headed sailing-dory, owned by a Union Boat Clubman whom I knew, lay over so far that her sail was submerged, and her centre-board came completely out of water. Only the head and clutching forearms of the two men aboard her could be seen. Afterward they told me they had been quite surprised by the squall. Beyond the Cambridge revetment wall a wide cloud of dust sprang up, hiding the "Builders" shed.
When this structure reappeared Adam gasped, then stood breathless, his countenance expressive of surprise.