They were verified by the detection at Rome, August 6, 1835, of a nearly circular misty object not far from the predicted place of the comet. It was not, however, until the middle of September that it began to throw out a tail, which by the 15th of October had attained a length of about 24 degrees (on the 19th, at Madras, it extended to fully 30),[279] the head showing to the naked eye as a reddish star rather brighter than Aldebaran or Antares.[280] Some curious phenomena accompanied the process of tail-formation. An outrush of luminous matter, resembling in shape a partially opened fan, issued from the nucleus _towards_ the sun, and at a certain point, like smoke driven before a high wind, was vehemently swept backwards in a prolonged train. The appearance of the comet at this time was compared by Bessel,[281] who watched it with minute attention, to that of a blazing rocket. He made the singular observation that this fan of light, which seemed the source of supply for the tail, oscillated like a pendulum to and fro across a line joining the sun and nucleus, in a period of 4-3/5 days; and he was unable to escape from the conclusion[282] that a repulsive force, about twice as powerful as the attractive force of gravity, was concerned in the production of these remarkable effects. Nor did he hesitate to recur to the analogy of magnetic polarity, or to declare, still more emphatically than Olbers, "the emission of the tail to be a purely electrical phenomenon."[283]
The transformations undergone by this body were almost as strange and complete as those which affected the brigands in Dante's _Inferno_. When first seen, it wore the aspect of a nebula; later it put on the distinctive garb of a comet; it next appeared as a star; finally, it dilated, first in a spherical, then in a paraboloidal form, until May 5, 1836, when it vanished from Herschel's observation at Feldhausen as if by melting into adjacent space from the excessive diffusion of its light. A very uncommon circumstance in its development was that it lost all trace of tail _previous_ to its arrival at perihelion on the 16th of November. Nor did it begin to recover its elongated shape for more than two months afterwards. On the 23rd of January, Boguslawski perceived it as a star of the sixth magnitude, _without measurable disc_.[284] Only two nights later, Maclear, director of the Cape Observatory, found the head to be 131 seconds across.[285] And so rapidly did the augmentation of size progress, that Sir John Herschel estimated the actual bulk of this singular object to have increased forty-fold in the ensuing week. "I can hardly doubt," he remarks, "that the comet was fairly evaporated in perihelio by the heat, and resolved into transparent vapour, and is now in process of rapid condensation and re-precipitation on the nucleus."[286] A plausible, but no longer admissible, interpretation of this still unexplained phenomenon. The next return of this body, which will be considerably accelerated by Jupiter's influence, is expected to take place in 1910.[287]