30 



Proceedings of the Hoy al Irish Academy. 



Computing the R.A. and Decl. from my ^ and 7;, the following 

 differences were found (Schultz minus Phot.) : — 



^0. 35 



Aa = - 0^-03 



A8 = - 3''-30 



82 

 122 

 196 

 287 



- -34 



- -04 

 + -12 

 + -15 



-f -70 

 -0 -47 

 - 1 -49 

 -1 -75 



The agreement is very satisfactory, considering the difficulty of 

 measuring these objects, except in the case of J^". G. C. 592, where the 

 difference in R.A. amounts to 0^-34. But Schultz has evidently not 

 seen this object well; his single results in E.A. differ 0**20 inter se, 

 while the AS are 105"-9, 107"-4, and 101"-2; and he remarks: 

 Contains several stars, place that of the brightest star in the south 

 part of the nebula." He seems, with his 9-inch object-glass, not to 

 have been able to distinguish clearly between the components of this 

 double nebula (my numbers 80 and 82), as his E.A. is half-way 

 between the E.A.s of the components (3P-10 and 3P-85), while his 

 declination is that of the south following one. ^0 changes have, 

 therefore, taken place in the positions of these five members of the 

 group during the last thirty years. 



