478 KRETZ. 



On the foregoing pages have been recorded the measures and 

 methods of reduction leading to the " Catalogue of Stars," p. 

 477, In general it will be better to measure a large number of 

 plates with less elaboration than has been done in the present case. 

 But owing to the very small number of existing photographs of 

 so early a date it was necessary, in order to get the best re- 

 sults, to employ all possible precaution to guard against errors. 

 The excellent agreement between Chase's determinations and 

 the photographic positions speaks well for the accuracy of both 

 researches. The proper motions cannot, of course, be verified 

 until a later date, but it seems safe to assume that all of those de- 

 pending on fourteen plates and on Chase's observations are very 

 nearly correct. It is to be regretted that their number is not 

 larger. The group is not well adapted to photographic work, 

 however. The range of magnitudes is large and the stars are 

 very scattered. In fact, it may be doubted whether the term 

 Group may properly be applied to these stars. The proper 

 motions certainly do not indicate any physical connection. 

 This matter, however, is of ulterior interest. 



In conclusion, I wish again to thank Messrs. Schlesinger and 

 Hays for aiding me in measuring the plates ; Dr. Davis for in- 

 valuable assistance in the catalogue work, and for freely placing 

 at my disposal his experience in all matters connected there- 

 with ; Professor Jacoby for his ever-ready counsel on all dififi- 

 cult points, and Professor Rees, Director of the Observatory, for 

 the interest he has shown in the work, and for securing its pub- 

 lication. It may also be mentioned that free use has been made 

 of the Observatory Contributions, especially of Dr. Davis' 

 " Fifty-Six Stars " and of Dr. Schlesinger's " Praesepe." 



(138) 



