86 THE COLOURED STAES ABOUT KAPPA CRUCIS. 



Since the above nothing seems to have been published about 

 the object, and I determined this year to examine it and see if 

 Mr. Abbott's statement that " certain changes are apparently- 

 taking place in the number, position, and colours of its com- 

 ponent stars," represented the actual state of the case. 



With this object in view I began the survey of which the 

 results are here given, including a catalogue of all the stars (130) 

 seen ; and a coloured map showing all these stars, also particular 

 notes made at the time of observation. The map takes in the 

 same space as Sir John Hersehel's, is similarly divided, but is on 

 a scale which makes it about four times as large. The 130 stars 

 are all that are now visible within the map's space with the 

 Sydney equatorial on the most favourable evenings. 



Grreat care was taken to render these results as accurate as 

 possible, and the positions of all the stars (33) which are visible 

 in full moonlight were determined with the position micrometer, 

 used as follows : — The single spider line was carefully adjusted to 

 a parallel of longitude, and then used as a transit wire over which 

 the zero star and all the others were allowed to pass, and the 

 differences of transit taken. In all cases the mean of two (or 

 more, as in some cases necessary for the satisfaction of the 

 observer) results is entered as one observation. While these 

 transits were being taken, one of the parallel wires was kept on 

 the zero star, and the other brought on the star under observation. 

 The micrometer screw then gave the exact difference in declination, 

 which was entered at the time. The micrometer results are given 

 in the notes, so that if necessary they may be referred to at any 

 future time. [&e Map and Catalogue.] 



As soon as these measures could be reduced, the positions of 

 the stars were carefully marked on a map of the size of the one 

 here given. Several of the stars were found to be different from 

 Hersehel's map — one especially (No. 11) was found to have moved 

 upwards of 6'- All these results were carefully verified, and on the 

 3rd April about 70 stars were entered on the map by eye-draft. 

 Additions and corrections were made till the total number 

 reached 130. 



The blue star Phi — one of those which has moved — I have very 

 carefully measured, and find it is not now in a straight line with 

 Delta and Epsilon ; neither will this line produced meet Zeta, 

 but passes some 5 seconds after it. The measures of this star 

 have been taken for the purpose of ascertaining if it has any 

 parallax. 



The night of April 12, being remarkably fine, was chosen for a 

 careful comparison of the map and the object seen in the 

 telescope. The magnitudes of all the stars were carefully 

 estimated, using the large stars as guides, and the differences 

 between my map and Hei'schel's carefully verified. 



