Page:The story of the comets.djvu/136



the periodic comets mentioned in the last chapter there are a large number of comets to which periods of far greater length have been assigned, amounting in many cases to thousands of years. It is obviously futile to talk about these as recognised members of the solar system, but there is a small group of 6 comets which may fairly be regarded as members of our system, although it must be confessed that at present only 3 out of the 6 have vindicated their claim by having appeared a second time. These comets are the following:—

It has been suggested that 4 of the above may have originally constituted a single comet; but independently of