The disc was not as perfect as those we have to-day; it was hooded to keep out exterior light, which is not necessary with the later instruments, and it was more unwieldy. However, it did its work, and did it well, in the hands of an experienced operator.
With only a nod to Barry, I turned the range band to maximum, and brought it swiftly to bear upon that portion of the city in which the little vial had fallen. As I drew the focusing lever towards me, the scene leaped at me through the clear, glowing glass disc.
Froth! Green, billowing froth that grew and boiled and spread unceasingly. In places it reached high into the air, and it moved with an eager, inner life that was somehow terrible and revolting. I moved the range hand back, and the view seemed to drop away from me swiftly.
I could see the whole city now. All one side of it was covered with the spreading green stain that moved and flowed so swiftly. Thousands of tiny black figures were running in the streets, crowding away from the awful danger that menaced them.
The green patch spread more swiftly always. When I had first seen it, the edges were advancing as rapidly as a man could run; now they were fairly racing, and the speed grew constantly.
A ship, two of them, three of them came darting from somewhere, towards the administration building, with its glass cupola. I held my breath as the deep, sudden humming from the Tamon told me that our rays were busy. Would they—
One of the enemy ships disappeared suddenly in a little cloud of dirty, heavy dust that settled swiftly. Another ... and the third. Three little streaks of dust, falling, falling....
A fourth ship, and a fifth came rushing up, their sides faintly glowing from the speed they had made. The green flood, thick and insistent, was racing up and over the administration building now. It reached the roof, ran swiftly....
The fourth ship shattered into dust. The fifth settled swiftly—and then that ship also disappeared, together with a corner of the building. Then the thick green stuff flowed over the whole building and there was nothing to be seen there but a mound of soft, flowing, gray-green stuff that rushed on now with the swiftness of the wind.