266 
Notices of Books, 
[April, 
year when first published, until 1890 ; moreover, it will not be 
as far from correctness, on account of precession, as existing 
Star Atlases, until the year 1927 ! The stars which are mapped 
include all down to the sixth magnitude inclusive, and are taken 
from the B. A. Catalogue and all other most available sources. 
The maps are drawn by Mr. Proctor himself. We predict a long- 
continued career of usefulness to this laborious work. 
Transits of Venus. A Popular Account of Past and Coming 
Transits. Third Edition. 
The Universe of Stars , Presenting Researches into, and New 
Views respecting, the Constitution of the Heavens. Second 
Edition. 
Other Worlds than Ours. The Plurality of Worlds Studied 
under the Light of Recent Scientific Researches. Fourth 
Edition. 
By Richard A. Proctor. London : Longmans. 1878. 
These works are second, third, and fourth editions of well-known 
treatises on popular astronomy, by that most indefatigable and 
industrious writer Mr. R. A. Proctor. In each instance the 
former editions have been revised, and in some respects modified. 
New discoveries have also been introduced, and these have in- 
creased as much in astronomy as in any other science. Of 
recent matters we have Dr. H. Draper’s discovery of oxygen in 
the sun by means of its bright lines ; also the discovery of the 
two small moons of Mars, which revolve around him in respect- 
ively 3°i and 7f hours, at distances of 14,000 and 5600 miles 
from his centre. A new star, which appeared in Cygnus, has 
faded into a planetary nebula, and it emits the monochromatic 
light of certain gaseous nebulae whose spectrum is a single 
nitrogen line. The calculations regarding the distance of the 
sun from the earth, founded on the recent observations of the 
Transit of Venus, appear to be drawing to a close, and they give 
an approximate distance of 93,000,000 miles. Mr. Proctor 
unites much learning with an easy popular style : he thoroughly 
understands his subjects, and has carried out much observational 
research ; moreover, he is an excellent draughtsman, and fre- 
quently gives us his own designs. Thus his books are at the 
same time popular and scientifically accurate, and they must 
always commend themselves to every class of reader. 
