A PLEA FOR THE STARS. 65 
it will be the northern hemisphere which will have more cold, 
and the southern less. 
This difference of temperature is a conspicuous, or at least 
quite appreciable, fact even now when the Earth’s orbit is nearly 
circular. 
But the Earth’s orbit is continually oscillating within certain 
limits of eccentricity, and the more eccentric the orbit the more 
conspicuous becomes this difference of temperature. The eccen- 
tricity of the orbit at present is only .o16 ; but 250,000 years 
ago—I quote the figures of Croll’s interesting computation— 
it was .0258; and 210,000 years ago—the last epoch of 
maximum eccentricity — it reached the ratio .0575 —a 
fraction which represents an appreciably elongated ellipse—an 
ellipse so elongated that (by Kepler’s Law of “equal areas in 
equal times”) the difference between the length of the period of 
cold and the period of warmth in each year would amount, in 
each hemisphere, in alternate cycles of 10,500 years, to a con- 
siderable portion of the year. Suppose the difference amounted, 
as a certain epoch, to three weeks—a term quite within the 
maximum limit—how enormous must be the effect of such 
a disparity. Give the northern hemisphere, for some thousands 
of years in succession, three weeks more winter, and three weeks 
less summer than at present, and its temperature would become 
so reduced as easily to account for all the phenomena of what is 
called the glacial epoch. 
I have been tempted into this digression for the purpose of 
showing how much closer is the connection than might at first 
be supposed between astronomy and biology. The instance 
may also stand as an illustration of the general interest of the 
subject under review. 
But I am happy to avail myself of a New Zealand publica- 
tion to set forth—beyond the general interest of the subject— 
the special attractions of astronomy for ourselves ; for ourselves, 
I mean, as living in the southern hemisphere. 
In view of the rich field of observation open to us, far exceed- 
ing in profusion, and in telescopic interest, that of our brethren 
in the northern hemisphere, it is lamentable to see how little 
scientific curiosity has been excited concerning it, and how little 
has yet been done. Take the latest edition of Proctor’s Atlas. It 
was constructed fornorthern observers, yet there is no southern atlas 
to take its place, and the student is compelled to use, as his very 
best available aid to the topography of the stars, a publication 
which he is obliged to read upside down. Not only so; the 
atlas, it is true, was not constructed to meet our requirements, 
and it is therefore unfair to complain, from our point of view, of 
its defects. But its defects, in the southern region, are of the 
most glaring character. Scores of interesting objects, all within 
the reach of instruments of moderate power, and all faithfully 
recorded by Sir John Herschel in his “Cape” observations, are 
conspicuous by their absence. So with the splendid manual of 
Mr. Edward Crossley. Some fifty, perhaps, of the better known 
