“These lines,” says Dr. Huggins, “possessed extreme interest, for there was certainly contained within this hieroglyphic writing some new information. A discussion of the position of these new lines showed them to be undoubtedly the same lines which appear in certain compounds of carbon. Not long before, Professors Liveing and Dewar had found from their laboratory experiments that these lines are only present when nitrogen is also present, and that they indicate a nitrogen compound of carbon, namely—cyanogen. Two other bright groups were also seen in the photograph, confirming the presence of hydrogen, carbon, and nitrogen.” It is worthy of notice that, only a few days later, Dr. H. Draper succeeded in obtaining a photograph of the same comet’s spectrum. It appeared to him to confirm Dr. Huggins’ statements, except only that the dark Fraunhofer lines were not visible—the photograph having probably been taken under less favorable conditions. So far, then, it seems clear that comets shine in part by reflecting sunlight, partly with light of their own; the part of the cometic substance which certainly shines with its own light is gaseous, and this gas in most comets “contains carbon, hydrogen, and nitrogen, possibly also oxygen, in the form of hydrocarbons, cyanogen, and possibly oxygen compounds of carbon.” But the latest comet has brought with it fresh news. Its spectrum is not like that given by the comets we have been considering. The bright lines of sodium are seen in it, and also other bright lines and groups of lines, which have not yet been shown to be identical with any belonging to the hydrocarbon groups, but probably are so. Dr. Huggins’ photograph shows, he considers, “that the original light of the comet, which gives a continuous spectrum (he means that portion of the original light which does so), was too strong to allow of the Fraunhofer lines being recognized in the reflected solar light.” We demur to this as being _shown_, it may fairly be said to be _suggested_. The cyanogen groups are not seen.