SCIENTIFIC SUMMARY. 
427 
listed during the last ten years. Surely, either Professor Tait or the 
reporters must have made some mistake. 
Further Observations of rj Ai'gus and the Surrounding Nebula. — Mr. 
Abbott submitted, two years ago, pictures of this interesting nebula to the 
Royal Astronomical Society, which seemed to show that the nebula had 
undergone important changes. He now sends a third picture, accompanied 
by comments on the criticisms to which his former paper was exposed. His 
first attack falls on Mr. Proctor, who, in an article in “ Fraser’s Magazine ” 
for December 1868 (presenting Mr. Abbott’s work in a very favourable 
light), had ventured to express doubts whether the stars in Mr. Abbott’s 
drawing of 1868 had been actually copied from the view given by the tele- 
scope, &c. Mr. Abbott says that all his drawings u were carefully copied 
from the object as described in the 1 Astronomical Register ’ for January 
1869 and he adds that “there is little doubt but that Mr. Proctor’s views 
on the subject would be very much enlarged, if he had the opportunity of 
seeing the star and nebula as they appear at Hobart Town.” Commenting 
on Mr. Abbott’s letter, Sir John Herschel, who had been the first to express 
doubts as to the placing of the stars in Mr. Abbott’s drawings, remarked 
that there w r as not one among all the stars delineated which he could 
identify with any of those laid down in his own drawings and catalogued 
positions. 11 The most superficial inspection suffices to show that there is no 
correspondence between us ; and that Mr. Abbott’s field of view of 1° 8' in 
diameter differs as completely from a similar field in my monograph, having 
7] Argus near the centre, as if the telescope had been directed to quite a 
different part of the heavens. . . . This would, however, be of little 
moment, were it permitted to suppose that attention had been given only to 
the delineation of the nebula, and that the stars had been put down at 
random, or with little regard to their real configurations. Mr. Abbott, 
however, in the paper which accompanies his diagram, distinctly repudiates 
this supposition, and insists on the correctness of his representations of the 
stars in the field of view delineated; not, indeed, as micrometrically 
accurate, but as careful eye-drafts.” Mr. Abbott having been communi- 
cated with as to the doubts thus renewed, replies, under date Febru- 
ary 7, 1871, endeavouring to re-establish the accuracy of his draughts- 
manship. Finally, the whole series of papers has been submitted to the 
searching scrutiny of the Astronomer Royal, who conceded the main points, 
namely, that the nebula has shifted its position, and that Mr. Abbott was 
the first to announce this interesting fact, yet comments, in somewhat 
severe terms, on Mr. Abbott’s drawings. “ When we look closely to funda- 
mental points,” says Professor Airy, u all is confusion. Mr. Abbott’s 
observations were all made with a refracting telescope, so that the order of 
N 
the four cardinal points on the map would be EgW (turned round in 
N 
in any degree). But in the 1870 map he has them marked Wg E ; in the 
1871 map he has marked only g . The ^ in the two maps differ about 
45°. In each of these maps is a line (different for the two) which he calls 
( Line of Light.’ What this means I have not the slightest idea. In 
points of geometry, therefore, Mr. Abbott is a most inaccurate man. As 
