26 PRESIDENT’S ADDRESS. 
sun (like our own), and then downward to the almost heatless and invisible 
ball. The period during which human life has existed on our globe is 
probably too short—even if our first parents had begun the work—to 
afford observational proof of such a cycle of change in any particular star ; 
but the fact of such evolution, with the evidence before us, can hardly be 
doubted. I most fully believe that, when the modifications of terrestrial 
spectra under sufficiently varied conditions of temperature, pressure, and 
environment have been further studied, this conclusion will be greatly 
strengthened. But in this study we must have regard also to the spectra 
of the stars themselves. The stars are the crucibles of the Creator. There 
we see matter under conditions of temperature and pressure and environ- 
ment, the variety of which we cannot hope to emulate in our labora- 
tories, and on a scale of magnitude beside which the proportion of our 
greatest experiment is less than that of the drop to the ocean. The 
spectroscopic astronomer has to thank the physicist and the chemist 
for the foundation of his science, but the time is coming—we almost see 
it now—when the astronomer will repay the debt by wide-reaching contri- 
butions to the very fundamenta of chemical science. 
By patient, long-continued labour in the minute sifting of numerical 
results, the grand discovery has been made that a great part of space, so 
far as we have visible knowledge of it, is occupied by two majestic streams 
of stars travelling in opposite directions, Accurate and minute measure- 
ment has given us some certain knowledge as to the distances of the stars 
within a certain limited portion of space, and in the cryptograms of their 
spectra has been deciphered the amazing truth that the stars of both 
streams are alike in design, alike in chemical constitution, and alike in 
process of development. 
But whence have come the two vast streams of matter out of which 
have been evolved these stars that now move through space in such 
majestic procession ? 
The hundreds of millions of stars that comprise these streams, are they 
the sole ponderable occupants of space? However vast may be the 
system to which they belong, that system itself is but a speck in illimitable 
space ; may it not be but one of millions of such systems that pervade 
the infinite ? 
We do not know. 
‘Canst thou by searching find out God? canst thou find out the 
Almighty unto perfection ?’ 
