105 



NOTES ON ATMOSPHEEIC METEOES. By ¥. Abbott, 

 r.E.A.S. 



It may be well to remind tlie present meeting of the great 

 amount of interest which is just now attached to Meteoric 

 Astronomy. The period of speculation on the little understood 

 objects, Meteors, dates from the time of Aristotle (330 B.C.), 

 and, although observations upon them have been carried on 

 ever since that time, little has been known, until recently, 

 respecting their height, velocity, and composition. 



That they are atmospheric will appear from their height, 

 which ranges from 35 to 75 miles, or a mean of about 60 

 miles, their speed, light, and detonating properties being about 

 equal to that of an electric spark. 



That they are astronomical will appear from their annual 

 appearance in unusual numbers on the 9th and 11th of 

 August, and again on the 12th and 14th of November. These 

 known dates have led to periods of prediction, from which it 

 is ascertained that the November meteors return in their 

 greatest magnificence every 38 years, so that their central 

 conjunction with the earth has been estimated by Professor 

 Newton, of Yale College, U.S., to occur as to-night or 

 to-morrow night, 13th or 14th November, 1866, when may be 

 expected a prodigious flight of meteors, the most imposing of 

 its kind, and which may not occur again during the present 

 century. 



As these fertile periods of meteors have not, to my know- 

 ledge, ever been observed in Tasmania, it will be interesting 

 to know if this prediction is verified. They are observed 

 usually to diverge from Leo, which constellation will rise 

 about 3 o'clock, a.m., at Hobart Town, but it will be well to 

 look for them about midnight and sunrise. 



For those who like to take part in this curious enquiry, I 

 have brought some blank forms which may be filled up at the 

 time of observation, according to the precept at the head of 

 the columns. 



