354 Ordnance Survey Astronomical Observations. 



steps of the redaction performed, are also given, up to the 

 complete result for latitude by each observation. 



In the subsequent part of the work, these quantities are 

 collated together, and special corrections applied for certain 

 instrumental peculiarities explained in the Introduction, and 

 for errors of assumed declination of the stars observed, which 

 being 491 in number, and confined between the parallels of 38° 

 and 68° N. decl., necessarily included many small stars whose 

 places had not previously been well fixed by any astronomer. 



In the concluding part of the Introduction, the final results 

 are considered, and being compared with the geodetical calcu- 

 lations, when the stations are but a few miles apart, some 

 most startling conclusions are arrived at ; shewing that the 

 latitudes of places are affected by many more causes than 

 most men's philosophy has hitherto taken account of. For 

 while the probable error of the astronomical determinations 

 is hardly so much as =£="•{?, their differences from the geodeti- 

 cal, are often ten to twenty times as great : nay, in one in- 

 stance, amount to the immense quantity of 9"*48. 



The number of discordances is at the same time no less 

 remarkable than their individual amount ; and amongst the 

 twenty-six stations observed are found all the following in- 

 stances : — 



Lat. Lat. Discordance* 



St Agnes, . 



49 53 and 



Goonhilly Down, 



50 2 



-1-60 



Southampton, . 



50 54 ... 



Boniface Down, 



50 36 



+ 1-23 





... . • . 



Week Down, . 



50 36 



+ 1-45 



... ... ■ 





Dunnose, . 



50 37 



+ 3-71 



... • • • • 





Port Valley, . 



50 39 



+ 0-42 



... ... • 





Black Down, . 



50 41 



-1-10 



Hungry Hill, . 



51 41 .'." 



Feaghmaan, 



51 55 



-3-73 



Forth Mountain, 



52 56 ... 



Precelly, . 



51 56 



+ 0-60 



Tawnymore, 



54 17 ... 



Lough Foyle, . 



55 2 



+ 3-20 



Ben Heynish, . 



56 27 ... 



Ben Lomond, . 



56 11 



+ 3-71 



Cowhythe, . 



57 41 ... 



Great Stirling, 



57 27 



-9-48 



North Bona, 



59 7 ... 



Monach, 



58 21 



-0-30 



... • 



59 7 ... 



Ben Hutich, . 



58 32 



+ 3-87 



Balta, 



60 44 ... 



Saxavord, . . 



60 49 



-2-03 



The — sign shewing that the geodetical is less than the 

 astronomical amplitude. 



