Transformation of a nebula which has entered into the sphere of the sun's attraction; continuous parabolic rings of nebulous matter–Similarity between the elements of the orbits of meteor streams and cometary orbits–The August stream; identity of the Leonides and the comet of 1862–Identity of the Perseids and the comet of 1866 (Tempel)–The shooting stars of April 20 and the comet of 1861–Biela's comet and the December stream–Did the earth encounter Biela's comet on November 27,1872?

It still remains to explain the origin of meteor swarms or streams, and the reason of their annual periodicity and the maxima which appear at dates separated by intervals of several years. For this purpose it will be necessary for a moment to quit the domain of fact and consider some theoretical speculations.

The swarms of shooting stars appear to be constituted, as it were, of aggregations of particles separated from one another by some distance. But if, instead of seeing them on their arrival in the proximity of the earth, in contact with its atmosphere, it were possible to contemplate them from a distance in the heavens, the whole of these myriads of particles, whether illuminated by the sun's rays or shining by their own light, would appear to the observer like a cloud or nebulosity.