504 



Proceedings of ihe Royal Irish Academy. 



2. TeajS^sit Instetxmeh't in BeRLIjST. 





Albrecht - 



- TiETJEN. 



Albrecht — Valentiner. 



1867. 



West: 



East. 



W. -E. 



1867. 



West. 



East. 



W.- 



-E. 



March 



9 



- 0^-27 



- 0^-03 



- 0=-24 



July 13 



-G^-U 



+ 0^-13 



-0= 



•27 





15 



- -18 



- 0-03 



-0 15 



14 



- 0-14 



+ -09 



-n 



•23 



July 



14 



- -33 



- -16 



-0-17 



15 



-0-05 



0-00 



-0 



•05 





15 



-0-29 



-0-18 



-0-11 



16 



-0-03 



+ 0-05 



-0 



•08 





16 



- -28 



- -14 



- -14 



Nov. 9 



- -12 



+ -09 



-0 



•21 



Sept. 



26 



-0-23 



-0-07 



-0-16 



12 



-0 -14 



-0 -01 



-0 



•13 











1 



27 



-0-05 



+ 0-13 



-0 



•18 







TlETJEN - VaLEXTINER. 



1 











1867. 



West. East. 



W. - E. 







July 13 



+ 0=-02 



+ 0^-30 



- 0>^-28 











15 



+ 0-05 



+ 0-31 



-0-26 









Each number is the mean result of from 5 to 12 stars. 



But the following results were found in Lund in Sweden, -witli the 

 Leipzig instrument, after the illumination had been altered'^" : — 



^'ALENTINER - 



- Backlund. 





1868. 



West. 



East. 



W. - 



-E. 



June 26 



- 0^-02 



0^-00 



-0» 



•02 



27 



+ 0^02 



-00 



+ 



•02 



28 



- 0^06 



- 0^03 



- 



•03 



30 



+ 0-03 



•OO 



+ 



•03 



Each number is the mean result of from 6 to 12 stars. 



Compared with these results, which are founded on numerous 

 observations, the researches made in Greenwich in 1852 and 1853, 

 with a "Binocular eye-piece," become of less importance, being 

 founded on rather few observations, but they are of a similar nature. 

 As already mentioned, this binocular eye-piece divides by a prism the 

 rays coming from the object-glass of the transit-instrument into two 

 parts, so that two observers simultaneously may observe a transit 



* Bestimmung der Langendiiferenz z-srischen Berlin und Lund. Lund, 1870. 



