Steel Mill "Comets" Dazzle "Smoky City"

1920

Brilliant Lights Flashed to the Sky Amuse Scientists.

PITTSBURGH, Pa. — Intense blast furnace activity, combined with low temperatures, has in recent weeks given to the Pittsburgh district some of the most beautiful "furnace comets" it has ever seen.

But they are gradually losing their brilliancy, and with the approach of spring, scientists say, they will vanish until favorable conditions reappear next winter.

"Furnace comets" are great broad shafts of yellow light which pierce the black background of a murky sky in a most spectacular manner. They flash almost without a moment's notice, only to reappear as bright, if not brighter, than before. Usually there are two of them, at times riding perpendicular, but oftener cutting the sky like the beam from a searchlight.

Scientists of the Allegheny observatory explained the lights by saying that the light from the blast furnaces penetrates the atmosphere above the city to a great height, and, there being caught by frost crystals, send back the reflection in the form of broad bands. For years they have passed almost unnoticed until this year, when, because of the continued operation of large numbers of furnaces, they became much more frequent.