260 DETERMINATION OF THE LONGITUDE OF SEVERAt. 



Calling 



^ = correction of Biirckhardt's semidiameter for Captain Tal- 



cott's transit instrument, 

 i' = a. similar correction for a European instrument, 

 t == + (i' — ^^ comparative correction, 



the above table gives, 



t ^"^ = + 0-19 for Captain Talcott's instrument with the Edinburgh 



5 



t^'^ = + 0-23 " « Greenwich, 



^(2) _ q: 0-23 « « Cambridge, 



t^^^ = qp 0-15 « « Kremsmunst., 



i^ = + 0-11 " « Cracow, 



i^'^ = + 0-30 « « Dorpat. 



Then T, being the result of a single comparison of Captain Talcott's 

 instrument with the Edinburgh, &c., we have the several results cor- 

 rected for the comparative values of the correction of Burckhardt's 

 semidiameter, the upper sign for the first limb, the lower for the se- 

 cond. 



= T + n i 

 = T + n 

 = &c. 



(0) 



(1) 



Applying the correction for all the instruments in this manner, and 

 taking the means for each day according to the weights w, and the 

 means for the several days according to the weights W, we find the 

 correction for this part of irradiation, of the final result for each sta- 

 tion, to be: 



'5 



Correction for station No. 1, near Huron, Ohio, — 0-72 sec. 

 « « 2, Turtle Island, -\- 0-28 sec. 



3, South Bend, — 2-56 sec. 



This hypothetical correction, it appears, must be rejected ; for on 

 submitting it to the best test which the nature of the subject furnishes, 



