Curiosities of Science. 



of the Observatory of Vienna, arrived at its least distance from 

 the sun a few minutes after eleven o'clock on the morning of 

 the 30th of September ; its longitude, as seen from the sun at 

 this time, being 36 13', and its distance from him 55,000,000 

 miles. The longer diameter of its orbit is 184 times that of 

 the earth's, or 35,100,000,000 miles; yet this is considerably 

 less than ToWth of the distance of the nearest fixed star. As 

 an illustration, let any one take a half-sheet of note-paper, and 

 marking a circle with a sixpence in one corner of it, describe 

 therein our solar system, drawing the orbits of the earth and 

 the inferior planets as small as he can by the aid of a magnify - 

 ing-glass. If the circumference of the sixpence stands for the 

 orbit of Neptune, then an oval filling the page will fairly repre- 

 sent the orbit of Donati's comet ; and if the paper be laid upon 

 the pavement under the west door of St. Paul's Cathedral, Lon- 

 don, the length of that edifice will inadequately represent the 

 distance of the nearest fixed star. The time of revolution re- 

 sulting from Mr. Loewy's calculations is 2495 years, which is 

 about 500 years less than that of the comet of 1811 during the 

 period it was visible from the earth. 



That the comet should take more than 2000 years to travel 

 round the above page of note-paper is explained by its great 

 diminution of speed as it recedes from the sun. At its perihelion 

 it travelled at the rate of 127,000 miles an hour, or more than 

 twice as fast as the earth, whose motion is about 1000 miles a 

 minute. At its aphelion, however, or its greatest distance from 

 the sun, the comet is a very slow body, sailing at the rate of 

 480 miles an hour, or only eight times the speed of a railway 

 express. At this pace, were it to travel onward in a straight 

 line, the lapse of a million of years would find it still travelling 

 half way between our sun and the nearest fixed star. 



As this comet last visited us between 2000 and 2495 years 

 since, we know that its appearance was at an interesting period 

 of the world's history. It might have terrified the Athenians 

 into accepting the bloody code of Draco. It might have an- 

 nounced the destruction of Nineveh, or of Babylon, or the 

 capture of Jerusalem by Nebuchadnezzar. It might have been 

 seen by the expedition which sailed round Africa in the reign 

 of Pharaoh Necho. It might have given interest to the found- 

 ation of the Pythian games. Within the probable range of its 

 last visitation are comprehended the whole of the great events 

 of the history of Greece ; and among the spectators of the comet 

 may have been the so-called sages of Greece and even the pro- 

 phets of Holy Writ : Thales might have attempted to calculate 

 its return, and Jeremiah might have tried to read its warning. 



Abridged from a Communication from Mr. Hind to the Times, and from a Leader 

 in that Journal. 



