1 6 THE POPULAR SCIENCE MONTHLY 



Path of Halley's Comet. 



tions extended for three or four weeks, and were made at Ingolstadt. 

 Apian first established the fact that the comet's tail is constantly 

 directed away from the sun. This was the first substantial item of 

 evidence towards showing that comets, instead of being simply terres- 

 trial phenomena, are in some way connected with the cosmic universe. 

 The system of Copernicus had not then appeared, so the true solution 

 of the problem could not be expected, though here at least was a begin- 

 ning. Earthquakes, showers of blood and fiery appearances in the 

 heavens are charged to this comet, but from now on, we have less and 

 less of these matters. The next appearance, 1607, was detected by 

 Kepler, though it had been seen a few days before by a monk in Swabia. 

 Kepler furnishes a series of observations from September 26 to October 

 26, but he was less fortunate in his speculations regarding its nature 

 and movements than had been his lot in his planetary researches. 



The year 1682 brings us again to Halley. In these attempts to iden- 

 tify the early appearances, the Chinese annals have been of great assist- 

 ance. In some cases all of the substantial evidence which we possess 

 comes from this source. These records were kept in a much more sys- 

 tematic manner than the chronicles of the western people. The times 

 when the comet was first and last seen are carefully recorded. The 

 path, observed among the stars, is often given, not, of course, with 

 extreme accuracy, but sufficiently so as to admit of the determination of 

 an approximate orbit, and thus furnish valuable data for identification. 

 The Chinese appear not to have been disturbed by the superstitious 

 dread of comets which pervaded Europe. Their accounts of the physical 

 characteristics are unsatisfactory, the length of tail and similar mat- 

 ters being given, not in angular, but in linear, measure, which, of 

 course, means nothing. 



