Spectrum of Coggia's Comet.

The Manufacturer and Builder 6, 1875

Spectroscopic obser vations on Coggia's comet, made at the Greenwich ob-servatory, show the spectrum of dioxid of carbon, (new name for carbonic acid gas.) When this gas was illuminated by the electric spark from an induction coil without a Leyden jar attached, the spectrum was nearly identical with that of the comet. Two bright bands were always coincident, but occasionally the coma of the comet gave a faint continuous spectrum in addi-tion, while the spectrum of the nucleus was always continuous, and contained numerous bright bands and three or four dark lines in the yellow and green.