16 BOHLIN, ON THE GALACTIC SYSTEM WITH REGARD TO ITS STRUCTURE. 
A more complete account of the distribution of the Nebulze is given by PRoCTOR! 
in the form of isographic projection charts, showing the concentration of these bo- 
dies into two great systems more clearly than a merely numerical table is able to 
do. The four pairs of maps are laid down from the table prepared by CLEVELAND 
ABBE. The author points out a somewhat stratified aspect of the northern group 
of nebulzge, which permits to understand the conception of W. HERSCHEL that the 
nebulzae might be arranged in a zone, somewhat resembling the Milky Way, but 
nearly at right angles to it. On closer inspection, he recognizes a certain streamy 
character of the groups in both hemispheres. "The pair of maps, numbered ITI, is espe- 
cially fit to bring out the great vacant zone, along the Milky Way, for the nebule&, 
which, according to the author, is to be considered as the most significant of all the 
features, presented by the nebular system. This and the further considerations of 
the author are closely related to the researches of CLEVELAND ÅBBE in his memoir 
just quoted. The assertion of Proctor with regard to his pair of charts, numbered IV, 
containing the stellar system together with the nebular scheme, that the lucid stars 
show a tendency of clustering at the same points, where condensations of nebulzg 
are prevailing, rests open to question. According to PRocTOoR, the vacancies of 
nebul&e in places of the heavens outside the Galaxy are marked by absence of 
bright stars. 
These valuable researches of PROocTOR induced a new investigation of the matter 
by SIDNEY WATERS.” The charts constructed by this author contain all the objects 
recorded in J. HERSCHEL”S general catalogue of 1864. They are very beautifully laid 
down and show plainly the mutual distribution of clusters and nebule. 
As a complement to the charts of the Globular Clusters, the present memoir 
contains also three pairs of maps, showing the distribution of the spiral nebule” in 
two vast dominions arround the poles of the Milky Way. The maps are confined 
to the nebulzxe designed in the New General Catalogue as bright B or very bright, 
vB. The three pairs of charts contain, respectively, the nebulz designed as 1) round R, 
2) extended or little extended E or I1E, 3) very extended or exceedingly exten- 
ded vE or eE. In every case the concentrations referred to are clearly visible, 
the dominions of the round nebule being the most vast and the very extended 
nebulz&e being most constricted towards the poles of the Milky Way. 
The mutual relation of the Milky Way and the dominions of the spiral nebulze 
seemed to mer; for long a time, to be the most wonderful enigma of the heavens, until 
the probable explanation of this behaviour revealed itself at a closer examination of 
the structure of the Milky Way. It is in fact impossible, by regarding the peculiar 
structure of the body of the Milky Way, to join in the spiral theory, attempted by 
some astronomers, and not to acknowledge its substantially circular form. The prin- 
LR. A. Proctor, Distribution of the Nebulge. Monthly Notices of The Royal Astronomical Society. 
Vol. XXNIN, 18690pag: 337. 
> The distribution of Clusters and Nebulée, Monthly Notices of the Royal Astronomical Society, Vol. 
ANKI 18733: Pag. 1058: 
3 A typical example of these nebulw is for convenience reproduced in Plate 6 N:o 7. 
