COMMENTATIO ASTRONOMICA. 



227 



SO observationes aestivae dant . . . ' 81° 36' 58" 464 



20 « hyeraales 59, 300 



Dififerenlia . . . 0",836, Brinklei adhibita refractione , reducitur infra 0",5, quae est 

 quarta pars differentiae a Brinkleio observatae. 



Sed observationes anno 1812 inslilutas , elsi minus faonas, si bis adjeceris , erunt 

 -differentiae : 



Refractio. Lyrae «. Aquilae «. Cygni x. 



Bradleiana. 0",572 1",092 0", 433 



Francica. 0',3 — 0",4 0, 5 circ. 



Pondius quidem hasce differentias non vult adscribi observationum errori, neque la- 

 ßien eliam parallaxi, sed causae externae cuidam haud admodnm absimili. 



«I shall , therefore, conclude thispaper, by expressing my hopes that, before a very 

 « long period shali elapse , the instrumenta lately erected may afford something more 

 k satisfactory and decisive. " 



Mox, 13 Martii 18[7, Pondius refert ad Societalem (») , se exeunte anno 1816 tenipe- 

 raturam internam externae aequasse, nuUam erroris indicis variationem detexisse, duo 

 quidem microscopia , non sex universa , legisse , sed numerosas et bouas tarnen esse Zy- 

 rae », Draconis y , Cygni «, et Aquilae » observationes. 

 \,y Lyrae «. 



50 observationes aestivae dant .•..••••.. 49",I9S 



34 « hyemales 49, 205 



2.) Draconis y. 



31 observationes aestivae ...,.....;.. 3",776 



33 « hyemales 3, 827 



3, ) Cygni x. 



37 observationes autumnales ....:...... 17'',36 



37 « hyemales 17, 28 



4.) Aquilae «, 



33 observationes aestivae ............ 30'',29 



45 « hyemales 30, 45 



« The. extremely small discordances , whicb is no doubt are accidental , happens ia 

 « some of the cases (chiefly with the French refractions) to be in a direction aC lea^ 

 « conirary to parallax. " 



« It now only remains to determine, wbeiher the fixed Instruments, lately erected 

 « für this particular inTestigation , will confirm tbc above result. " 



Dtiu 



(* ) PAj7, Transi !• modo I. p. 178. Titulus ejti Appendix to Mr, Pond's papee <m parattas. 



Ff 2 



