472 Scientific Proceedings, Royal Dublin Society. 
much to be done in this direction, but another important field 
was opened up by taking micrometric measures of groups of 
nebule or of nebulz and neighbouring stars. Into the text have 
been introduced diagrams of such groups or of a nebula and the 
stars near it, while four plates contain lithographic reproductions 
of more elaborate sketches, which had not already been published 
among the engravings in the former papers. How much more 
detail is given in the new publication than in the paper of 1861 
may be seen from the circumstance, that while the fourteen hours 
of RA in the latter only cover 34 pages, do they in the new paper 
extend over 129 pages. 
Since the “Supplement to the General Catalogue” came out in 
1878, the following notes on new nebulze have been published :— 
1. In the Comptes rendus for December 2, 1878, M. 
Stephan has a list of 837 nebulz. Of these, however, numbers 8 
and 9 are quite certainly identical with 5380 and 5883, while 10 
and 11 seem = 5385 and 86. 
2. M. Tempel has given the places of 26 nebulz not in the Sup- 
plement in the A. N. 2212. In No. 2253 he has again a nova, 
and in No. 2269 also one. 
3. Dr. C. H. F. Peters gives the place of a new nebula in the 
A. N, 2256. 
4. Mr. Burnham has two nebule in the Mem. R. A.S., XLIV., 
p. 169. (Another, abid., p. 216, already mentioned in his third 
list of double stars, and accidentally overlooked by me.) 
5. One found by M. Block, of Odessa (3" 33™-9, 116° 44’ 
for 1880), A. N. 2287 (the other one he mentions is = 5,315). 
6. The Birr observations contain here and there some new 
nebule, nearly all found after the Supplement had been printed. 
The » D.M. + 41°, 4004, was towards the end of 1879, by the 
Rey. T. W. Webb, found to be nebulous, and its spectrum was at 
once found to be gaseous by Copeland, Vogel, and others. The 
nebulous character of this star had already been noticed by M. 
Stephan, in whose above-mentioned list it is No. 27. 
A series of measurements of all the planetary nebule has been 
commenced with the 15-inch refractor of the Harvard College 
Observatory. Their diameters are measured, and when they are 
elliptical, also the directions of their axes. As it is of importance 
to be able to ascertain the general character of the spectrum with- 
