SECT, xxxvi.] THE COMET OF 1843. 401 



the period of its revolution, renders it impossible to form 

 any idea of the number of centuries which must elapse be- 

 fore this event takes place. 



The same cause may affect the motions of the planets, 

 and ultimately be the means of destroying the solar system. 

 But, as Sir John Herschel observes, they could hardly all 

 revolve in the same direction round the sun for so many 

 ages without impressing a corresponding motion on the 

 ethereal fluid, which may preserve them from the accumu- 

 lated effects of its resistance. Should this material fluid 

 revolve about the sun like a vortex, it will accelerate the 

 revolutions of such comets as have direct motions, and 

 retard those that have retrograde motions. 



The cornet which appeared unexpectedly in the beginning 

 of the year 1843 was one of the most splendid that ever 

 visited the solar system. It was in the constellation of 

 Antinous in the end of January at a distance of 115 millions 

 of miles from the earth, and it passed through its perihelion 

 on the 27th of February, when it was lost in the sun's rays ; 

 but it began to be visible about the 3rd of March, at which 

 time it was near the star Iota Cetse, and its tail extended 

 towards the Hare. Before the passage at the perihelion it 

 had no tail, but at that epoch the tail suddenly darted out, 

 and extended to a distance of 1826 millions of miles in 

 about an hour and a half; a most inexplicable speed of 

 development, which indicates some powerful repulsive force 

 at the moment of the greatest proximity to the sun, at 

 which time the tails are formed. The brightness of the 

 comet and the length of its tail continued to increase till 

 the latter stretched far beyond the constellation of the Hare 

 towards a point above Sirius. Stars were distinctly seen 

 through it, and when near perihelion the comet was so 

 bright that it was seen in clear sunshine in the United 

 States like a white cloud. The motion was retrograde, 

 and on leaving the solar system it retreated so rapidly at 

 once from the sun and earth that it was soon lost sight of 



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