36 ASTRONOMICAL OBSERVATIONS. 



The above difference of 1 3" in time, is equal to an angle of 

 I' 5" in fpace, which in this cafe is the error of our line towards 

 the eall, and was correfted on a bafe of 1 1 o perches. 



On the 1 6th of July, dillant from our firft pofition 29 miles, 

 we examined the dire£i:ion of our line by the following ob- 

 fervations. 

 DifF. in time between the paflage of jj. Sagit. and y 



Draco, over our line. 



} 



' 9 20."5 



From the above obfervation it appears that our direction is 

 fufliciently accurate, and the fmall error if it can be called one, 

 is to the eaft. 



September 3d we made the following obfervations to reftify 

 the direction of our line. 



Diff. in time between the pafTage of a Urfsc Majoris, and! h . en 



y Cephi. over our line. - - - J 



Right Afcenfion of y Cephi. 1 1' 22° 40' 53" 

 Do. of ^ Urfx Maj. 5 12 3; 18 

 Diff. - - 6 10 5 35 



Deducl 6'. - _6 



o 10 5 35 = in time to o 40 22 



Error in time - . - -004 diff. 



By this obfervation it appears that our line is direfted too 

 much towards the eaft by an angle of 13". 



Diff. in time between the palfage of a Urfse Minoris, and") o'' 5' S" 



f UrPie Majoris over our line ... J 



Right Afcenfion of a Uifce Min. o' 12° 34' 13' 

 Do. otaUrfxMaj. 6 11 7 24 



6 I 26 49 



Dedua - - _6 



Difference - o i 26 49 = in time to 0547 



Error in time - - - - o o J9 diff. 



By this obfervation, it appears that our direftion is too much 

 eaft by an angle of 23". 



2 . Error 



