8o REPORTS ON INVESTIGATIONS AND PROJECTS. 



tions. It was seen at once that this offer, successfully made good, 

 would remove the most serious blemish to be anticipated in the Pre- 

 liminary' General Catalogue — the extreme weakness of existing 

 material for computing the proper motions of manj- of the far south- 

 ern stars. It was believed that the great improvement in results to 

 be anticipated from these southern observations would far more than 

 compensate for the dela3^ Accordingly, Sir David Gill's offer was 

 accepted. Advantage will be taken to strengthen the determination 

 of motion for about 600 of the stars north of — 33° by special obser- 

 vations at the Dudley Observatory. These observations are already 

 in progress. The completion of the Preliminary General Catalogue 

 should easily be effected during 1906. Every effort will be made to 

 insure against an}' default in this anticipation. 



During the year several valuable transcripts of unpublished obser- 

 vations have been received for use in the preparation of the Prelim- 

 inary General Catalogue. Notable among these contributions are : 

 Positions from the new reduction of Groombridge's observ^ations, 

 1810, and advance sheets for the entire catalogue, from the Astron- 

 omer Royal, Greenwich ; transcripts of several thousand positions 

 from the new reduction of Henderson's ob.servations, 1S40, from Dr. 

 Halm, acting for Dr. Copeland, Astronomer Roj-al for Scotland ; 

 about 4,000 star-positions from the unpublished catalogue of the 

 Cincinnati Observatory for 1900, from Dr. Porter, director ; com- 

 plete transcript of the unpublished Berlin Catalogue for 1890, from 

 Dr. Kiistner, director of the observatory at Bonn ; a complete tran- 

 script of all the later unpublished observations of the Melbourne 

 Observatory, from Mr. Baracchi, director (these cover observations 

 extending over the past twenty years) ; positions of many stars from 

 the unpublished recent observations at the Cape Observatory, from 

 Sir David Gill. All of the observations are of very great use in our 

 work because they relate either to very earh' or very late epochs, 

 thus very greatly increasing the weight of determination for very 

 man}' of the proper motions in our proposed catalogue. All these 

 gentlemen, as well as others, are deserving of cordial thanks for the 

 sympathetic and practical interest the}' have taken in this work. 



In the division of observations during the past year much work 

 of fundamental usefulness in relation to future operations has been 

 accomplished. The use contemplated for the transit-circle in the 

 projected obser\'ations, now actually begun, requires that, among 

 others, two sources of error should be accurately investigated — devia- 

 tion of the telescope from a plane normal to the axis of revolution, 

 and error of graduation of the circles. These errors, always impor- 



