REVIEWS. 
349 
necessarily be a certain amount of distortion ; but in those before us the 
degree of distortion is considerably less than in those formerly employed, 
owing to the adoption of the dodecahedron instead of the cube in the cir- 
cumscription of the sphere. As the author very properly observes, a set of 
star-maps for popular use should fulfil the following conditions : — (1) The 
celestial sphere should be presented in a moderate number of maps ; (2) on 
the Gnomonic projection ; (3) with moderate distortion ; (4) with moderate 
variation of scale ; (5) with the relative positions of the constellations of 
each hemisphere visible at a glance. Now, in the maps at present in use it 
is well known that there is, as must be from their construction, excessive 
distortion, great variation of scale, and the equator, for the same reason, 
divides four of the six maps into equal parts, corresponding to the northern 
and southern hemispheres respectively. 
Mr. Proctor has obviated the errors to which we have referred by pro- 
jecting the stars upon the circumscribed dodecahedron, which, as can be 
shown mathematically, is the only form in which the five conditions above 
mentioned can be best satisfied. His maps form twelve pentagonal maps, 
arranged in two plates — the first containing the north polar and five northern 
maps, the second the south polar and five southern maps. The angles of 
each pentagonal map correspond to points separated by an arc of 37° 22' 38” *5 
from the principal point. The five outer maps are placed in immediate juxta- 
position with the central or polar one, and the neighbouring edges of the 
five outer ones are not so far separated as to prevent the student identifying 
the divided constellations. All the stars in the Astronomical Societies’ cata- 
logue, down to those of the fifth magnitude, are included in Mr. Proctor’s 
delineations ; and the right ascension and declination of them, about 1,500 
in number, have been calculated from the values and variations given in that 
catalogue. In order to give the student a clear conception of the nebulae, 
two black maps, on which the stars and milky way, minus the constellations, 
have been carefully drawn, are added. Plates I. and II. are handsomely 
coloured, and on those also, though less distinctly, the milky way is repre- 
sented. Mr. Proctor has written a most useful introduction explanatory of 
his maps ; in this he contends, in a manner whose accuracy cannot be dis- 
puted, for the superiority of his method of projection over that of other 
astronomers. We have read his remarks with attention and profit, and we 
have much pleasure in commending his maps of the stars to all who are 
interested in astronomical pursuits : they are convenient, precise, and easily 
intelligible, and convey at a glance an idea of the relative positions of the 
stars, which could not be obtained in a month’s study of the common celestial 
globe. 
NOTES ON EPIDEMICS.* 
T HIS volume is the expanded reprint of an article which appeared in 
the January number of the British Quarterly Review ^ and which the 
* “ Notes on Epidemics, for the use of the Public.” By Francis E. 
Anstie, M.D., F.E.C.P. London : Jackson, Walford, & Hodder. 1866. 
2 b 2 
