14 é REPORT—1905. 
ultimate parts of the atom within the range of our ordinary scales of 
measurement. 
IT have already considered what would be observed under the triply 
powerful microscope, and must now return to the intermediate stage of 
magnification, in which we consider those communities of atoms which 
form molecules. This is the field of research of the chemist. Although 
prudence would tell me that it would be wiser not to speak of a subject of 
which I know so little, yet I cannot refrain from saying a few words. 
The community of atoms in water has been compared with a triple 
star, but there are others known to the chemist in which the atoms are 
to be counted by fifties and hundreds, so that they resemble constella- 
tions. 
I conceive that here again we meet with conditions similar to those 
which we have supposed to exist in the atom. Communities of atoms 
are called chemical combinations, and we know that they possess every 
degree of stability. The existence of some is so precarious that the 
chemist in his laboratory can barely retain them for a moment ; others 
are so stubborn that he can barely break them up. In this case dissocia- 
tion and reunion into new forms of communities are in incessant and 
spontaneous progress throughout the world. The more persistent or more 
stable combinations succeed in their struggle for life, and are found in 
vast quantities, as in the cases of common salt and of the combinations 
of silicon. But no one has ever found a mine of gun-cotton, because it 
has so slight a power of resistance. If, through some accidental colloca- 
tion of elements, a single molecule of gun-cotton were formed, it would 
have but a short life. 
Stability is, further, a property of relationship to surrounding con- 
ditions ; it denotes adaptation to environment. Thus salt is adapted to 
the struggle for existence on the earth, but it cannot withstand the 
severer conditions which exist in the sun. 
Thus far we have been concerned with the almost inconceivably 
minute, and I now propose to show that similar conditions prevail on a 
larger scale. 
Many geological problems might well be discussed from my present 
point of view, yet I shall pass them by, and shall proceed at once to 
Astronomy, beginning with the smallest cosmical scale of magnitude, and 
considering afterwards the larger celestial phenomena. 
The problems of cosmical evolution are so complicated that it is well 
to conduct the attack in various ways at the same time. Although the 
several theories may seem to some extent discordant with one another, 
yet, as I have already said, we ought not to scruple to carry each to its 
logical conclusion. We may be confident that in time the false will be 
eliminated from each theory, and when the true alone remains the recon- 
ciliation of apparent disagreements will have become obvious. 
The German astronomer Bode long ago propounded a simple empirical 
