334 OIRARDl REGNERI POCKENS 



« The uncerlainly, Iherefore, respecting Ihe relative distances, aa deduced from Iheif 

 V degrees of briglitncss, treäkeris Gorielusions against parallax drawn from differences of 

 « north polar disUaces of stais having nearly the same right ascension , and north polar 

 « distance. " 



« To many, tha time amd labour spenl in Ihis niinute enqpiiry, may appear wasled. 

 (( Some however will juslly appreciate the exeriions ihat have been made here and at 

 <i Greenwich. Several allempts lo obsPTre the parallax of the fixed stars have failed 

 « since the time of Dr. Hooke, and Mr. Flamslead, and if it should eud like the 

 « rest , it will be some satisfaolion td hate asfcertainod , beyond doubt , certain limits ; 

 (( and also , probaWy lo Itave oceasioned these limits to be still farther circumscribed by 

 « the observatioHS of Mr. P oad, in the event of his not confirming my conclusions. " 



§ iS. 



Ad haec Pondius (f), seriptioncm memorans Brinkleianam : «The argu» 

 « ments" inquit , « and observatious, wliich it contains, are such as no doubt require 

 (' very atteriüve consideratiori; biit I think some of Dr. Brinkley's doubts hav6 ari- 

 « sen frora my not having myself been sufficiently explicit as to the details of my 

 « own observatious , and the precautions I have iised. However this may be , it seemed 

 i< to me more than ever desirable to Institute some new process of investigation , to 

 « which none of Dr. Brinkley's objections could possibly apply ; and it has occurred 

 « to me , that perhaps the observations made with the new transit Instrument might ba 

 « suiSciently exact for this purpose , though taken under very unfavourable circumstan- 

 « ces. This was a question to be easily determined by inspection , and I have the sa» 

 « tisfaction lo State, that I find the observations of « Aquilae , already made, quite 

 « sufficienl to estalilish this important point ; namcly , Ihat the parallax of this Star iä 

 « either an insensible quantity, or is so extremely sniäll, that it cannot possibly have 

 « had any share in producing the discordances observed by Dr. Brinkley. " 



Insequitur autem haec altera scriptio lecta Maji 28, 1818 (*). 



« The atars, of which I have a sufficienl number of observations for this investigation 

 <( are a Aquilae, Arclurus» Gapella, and » Lyrae. Sirius is comparatively but seldom 

 <. observed , from its vicinity to the horizon. As the observations of all the above stars 

 « give the same result , it will be sufficieat lo 3elect one as an example. I have choseii 



« » 



(t) Fhil Trans, loco supra laudatoj 



(*) r/iil. Trans, i8i8. p. 48i. xxn Titulas est: On the paratlax of the fixed stars in right Of 

 sension. Sy John Pond. S. B. S. Astronomer Rojal, 



