ASTRONOMICAL PAPERS. 



4i 





i 



our cxpcdatioiis could not be fully anfwered by the obfer- 

 vatiions that were then made; as it was eafily forefeeii that 

 much greater precifion might be attained, from the advan- 

 tageous circumftances that would attend the tranfit in 

 1769. The great proficience, which the aftronomers 

 made in fettling this fundamental element, beyond what 

 was ever known before, has only raifed their expedations 

 and engaged their attention to improve every advantage, 

 that can be derived from a careful obfervation of this tran- 

 fit. If they have not been difappointed by unfavourabl 

 weather, we hopefor the utmoft certainty that can be gain- 

 ed in this n^atter, from the obfcrvations they have made, 

 when they fhall be compared together. But after all, we 

 muft fit down with thedifagreeablc aflurance that the dif- 

 tance of the Sun cannot be determined by them, let them 



be made with ever fo great accuracy, within many thoufand 

 miles; which will not appear ftrange, when we confidcr 



that his diftance is upwards of 94 millions of miles, and 

 that an error of a fingle fecond in his parallax will give an 

 uncertainty of 10 or 11 millions of miles in his diftance. 



This approximation, however, is fo much greater than 

 could be expeded, from any other method, that has ever 

 been propofed, that it has defervedly engaged the attention 

 of every civilized nation in the world ; and it muft redound 

 to the honor of our fociety, that they have taken fuch ef- 

 fetSlual care to have proper obfervatories eredcd, to furnifli 

 them with the neceffary inftruments, and to appoint pro- 

 per perfons, to ufe them on that occafion. 



As the credit of our obfcrvations, and the ftrefs that 

 will be laid upon them, in determining the parallax of 

 the Sun, will greatly depend not onlyon the care and fldll 

 of the perfons, that made them, but alfo on the goodnefs 

 of the inftruments, with which we were furniflied; it has 

 been judged proper to give the public the following ac- 

 count of our apparatus, and of the pains wc have taken to 

 have It in the beft order. 



4^ 



Vol. I 



F 



As 



