198 



GERAn T)I REGNERI FOCKENS 



« such as U;e pvecession , aberration , and nufniion; it may be of singuIar ijse , to exa- 

 « mine nicely the relative siluations of parlicular stars: and especially of thosc of llie 

 « erealest liistre , which it may bc jjresumcd lic nearcst lo us, and may iherefore 

 « be subject to more sciisible changcs; either from iheir own motion , er from Ihal of 

 « our System. And if at the same timc that the brighlcr stars are compared with each 

 « otbcr, WC likcwise determinc the relative posilions of some «f Ihe smallest tliat ap. 

 « peat near tliem , wliosc places can be ascertaincd wilh sufficient cxactness; we may 

 * perliaps be able to judge to what cause the cbangc , if any be observable , is owing. 

 « The uncertainty that wc are at present under , wilh rcspcct to the degree of accuracy 

 « wherewilh former astronomers could observe , makes us unable to determine several 

 ,, thin^s, relaling to the suhjeet that I am now speaking of: but the improvements , 

 « which have of late years been made in tho methods of taking the places of the hea- 

 n venly bodies, are so great, that a few years may hereafter be sufficient, to setlle so- 

 ft me points ; which cannot now be sellled , by comparing even the earliest Observation» 

 « wilh those of the present age. " 



Deinde admonct astronomos, inslrumentis bonis itistructos, ut in hunc finem observent 

 ßtellas in primis zenithales. Concursus astronomorum enim in eodem elemento definien- 

 do versantium efficiet, ut harmonia eventuum nullam relinquat de instrumento suspi- 

 tionem. Denique comiter et urbane rationem palam reddit , cur hanc inventionem primuni 

 conunuaicet cum comile de Macclesfield. 



AETAS POSTERIOR. 



A BBADLEIO AD BESSELÜM. 



1750 — 1830. 



1 DETECTIS STELLAKüM MOTIBUS AD POSITA KOVAK 

 ASTROnOMIAE FUKDAMEKTA. 



§ 1 



Jnitium capit ab hoc anno, quo alterum incipit saecuH praecedentis dimidium, — ini- 

 tium capit a nutatione detecta , — tertia historiae parallaxeos aetas. Exstitit enim sab 

 hoc tempus, auctore Bradleio, cum in omni astronomia ingens rerum conversio , tun» 

 parallaxeos detegeudae , lauquam post aestum tranquillitas , ita quaedam veluti de«- 

 peranlia. j.^ 



I 



