252 
SUNSETS IN AUSTRALIA 
The next great fact we notice is that in each successive 
stage passed through by any higher organism there is a 
corresponding modification in the relationship between the 
organism and its environment. If we note the structure, 
form, specific gravity, chemical composition, or temperature, 
we shall as we ascend the grades of organisms find them 
more and more distinguished from their inanimate media. 
Thus the development of an individual organism is at the 
same time a differentiation of its parts from each other and a 
differentiation of the consolidated whole from its environ¬ 
ment. 
The growth of an organism is carried on by the abstrac¬ 
tion from the environment of substances like those of which 
the organism is composed. In like manner the development of 
the organism, the production of each organ within the 
organism, is carried on by abstracting from the substances 
contained within the organism those required by the par¬ 
ticular organ. 
From all the facts of development we deduce the great 
and important generalisation that development is a change 
from incoherent, indefinite homogeneity, to coherent, defi¬ 
nite heterogeneity, and the profound principle Evolution 
receives further confirmation. 
SUNSETS IN AUSTRALIA. 
The sunsets have been magnificent here, even quite lately; 
but the displays are now intermittent and usually occur during 
times of high barometer. I have taken throughout a great 
number of observations, but have failed to establish a satis¬ 
factory connection between the “ glows” and other meteoro¬ 
logical factors prevailing at the earth's surface. That the 
glow is not due to vapour primarily, as suggested by Mr. 
Ellery, of Melbourne, seems certain. On occasions of 
magnificent displays I have had a perfectly sharp “clean” 
spectrum, without a trace of vapour-bands. Vapour condensed 
by dust particles may, however, “manipulate” the glow. Often 
in the forenoon the pink effects have been visible, even a few 
days ago; and at sundown, under conditions of high pressure, 
the display well-nigh baffles description, bathing the landscape, 
with its white-trunked gum trees, in tints so weird that one is 
tempted to imagine he is living on some other planet. Some 
ten days ago an intense burning glow was reflected from the 
western sky for fully an hour after sundown, giving one the 
