Astyo}W)iii(((l Sucieh/. 465 



Although the appearance of so many comets in one year 

 had been mentioned as a remarkable phaenomenon, yet he 

 would not wish to be understood as supposing that such a cir- 

 cumstance had never previously occurred, nor was likely to 

 occur again. The fact was, that from the great attention which 

 had been paid by astronomers to the discovery of these bodies 

 within these few years, and the interest excited by the investi- 

 gation of the laws by which they were governed, a more than 

 ordinary diligence had been employed in searching for them. 

 And there was every reason to believe, that if there were more 

 labourers in the field, a still richer harvest would ensue : from 

 which there might fairly be expected some additional light on 

 the laws and constitution of the imiverse. 



The President likewise called the attention of the members 

 to the circumstance of the opposition of Mars in the month of 

 May in the ensuing year. It was well known, he remarked, 

 that by a comparison of the observations of this planet with the 

 stars which were near it at that time, made at places situated 

 in these latitudes and at other latitudes having considerable 

 southern declination, the parallax of the planet might be rea- 

 dily deduced, and thence the pai'allax of the sun. As there 

 were, at this time, two active observatories in the southern he- 

 misphere, where this phaenomenon would probably be attend- 

 ed to (as it had been at the two preceding oppositions), it 

 were extremely desirable that corresponding observations 

 should be made in the northern hemisphere ; without which, the 

 observations made in the south would (as far as this subject is 

 concerned) be rendered of little or no use. He trusted, there- 

 fore, that those practical astronomers who were possessed of 

 the requisite instrinnents (and they were by no means complex 

 or expensive) would attend to this phaenomenon, and record 

 the observations which they might have the advantage and op- 

 portunity of making ; the uncertainty of this climate render- 

 ing it extremely desirable that all those, who had the means, 

 should unite in so useful an undertaking. 



For the convenience of such observers, the President an- 

 nounced that he had computed the right ascension and decli- 

 nation of six stars, near which Mars would pass a few days 

 before and after his ojiposition; these being the whole which 

 he could find in any of the catalogues. They were here offered 

 only as a mean of identifying the star with which the planet 

 may be compared. It was ])robable that other stars mightbe 

 seen, in the field of view of the telescope; and that even some 

 of these might not be found : for the catalogues of the smaller 

 stars are still very imperfect. It would render observations of 

 this kind more complete and useful, if regular observations of 



Vol. 66. No. 332. Z)ec. 1825. 3N such 



