THE 



POPULAR SCIENCE 

 MONTHLY, 



JANUARY, 1910 



HALLE Y'S COMET 



By Professor C. L. DOOLITTLE 



THE FLOWER ASTRONOMICAL OBSERVATORY 



IN what will be said in this connection respecting comets in general 

 and Halley's comet in particular, it will not be necessary to occupy 

 much space in repetition of the well-known series of ancient views re- 

 specting the physical nature of these bodies or the superstitious dread 

 with which they were regarded. With reference to the latter phase of 

 the subject it may be said in passing, that it was not altogether an un- 

 fortunate matter, as without this incentive, probably even such frag- 

 mentary and unsatisfactory records of comets as have come down to us 

 would not have existed. 



These accounts are very seldom of much service from a scientific 

 point of view. Very few seem ever to have thought it worth while to 

 measure the position of a comet, or to record anything that would help 

 us to-day in the determination of its orbit, or in identifying it with 

 earlier or later appearances. It was believed that they were meteoric 

 in character, occurring like the aurora borealis only a few miles perhaps 

 above the earth's surface, and subject to no uniform laws like the 

 heavenly bodies. This applies to the western nations simply. We shall 

 see that the Chinese were at least a little more rational in their methods, 

 though little as to their ideas on this branch of astronomy is known. 

 There are, however, among the ancient writers, two whose utter- 

 ances regarding comets are worthy of some attention, Diodorus Siculus 

 and Seneca. The former wrote a voluminous universal history in which 

 matters of authentic history are indiscriminately jumbled with myth 

 and fiction, all apparently being considered of equal value. Among 

 these, this statement occurs. "The ancient Egyptians and Chaldeans 

 derived from long series of observations, methods for predicting the 

 appearance of comets." As earthquakes and hurricanes were also 

 occurrences which they were said to be able to predict, it seems to be the 



