regarding their constitution and structure upon some of which it was hoped light would be thrown by improved methods and appliances. The spectroscope had revealed hydrogen and hydrocarbons in the tails of comets. But the comets, though of large volume, were insignificant in mass. Bulking sometimes hundreds of times as large as the sun, they contained less substance than an asteroid ten miles in diameter. Their tenuity was almost inconceivable—a state of rarefaction exceeding the most perfect vacuum that could be produced artificially. Comets possessed a light of their own beside that reflected from the sun, but its nature was not yet determined.

Both papers were fully illustrated with lantern-slides, including a fine series of photographs of the approaching comet taken at the Meeanee Observatory, Napier.