18 Anniversary Address. 



with some perseverance, that these falling stars were merely elec- 

 trical meteors. I have since found that I was mistaken ; but Mr. 

 Espy, in America, and other writers besides myself, dissented also 

 from the view taken of them by Dr. Olmsted. So much evidence 

 has been since collected, that without denying that there may be 

 meteors due to electrical action, it is maintained with every 

 ground of reason, that the displays in question are occasioned by 

 the earth in her orbit crossing or coming near a vast elliptical 

 hoop or band of solid bodies revolving round the sun, and about 

 90,000 miles broad, which is subject to undulations that occasion- 

 ally throw them out of their usual course, so that the earth en- 

 counters them sometimes unexpectedly. As the calculated 

 velocity of such bodies is from 18 to 36 miles per second, and as 

 the heat generated by friction with the earth's atmosphere at 

 such velocities would, according to Tyndall, cause combustion 

 and volatilization in some instances, we may account for the 

 brightness of the meteors and the infrequent discharge of Aerolites, 

 though these must be far more numerous than is generally 

 known. 



The Zodiacal light is also held to be of similar constitution, 

 and one of Professor Tyndall's conjectures is, that these meteoric 

 bodies constantly falling into the sun, and battering him with 

 indescribable force, are sources of that heat which requires to be 

 continually renewed. 



The 13th November, 2nd January, 20th April, and 10th August, 

 are days when these displays are most common ; but it has been 

 determined that there are fifty occurences annually, each with 

 its proper Radiant, or point in the heavens, from which they 

 appear to proceed. Such a display has not been seen, I believe 

 in Australia ; at least, though I have seen many grand meteors 

 here (which might be connected with such a shower), I have never 

 witnessed any such display as I saw m 1834. The Cape of 

 Good Hope is in nearly the same parallel as Sydney, and in 1832 

 the shower was visible at the Cape Observatory a quarter of an 

 hour before ix reached Great Britain, the earth in two hours 

 having passed through a stream of these meteors 30,000 miles in 

 thickness. 



It is much to be desired that the planetary influences would 

 produce such an undulation as would bring the meteoric stream 

 over this colony. 



