152 
the assumed value of the constant of the aberration of light 
gave another quite independent result, agreeing very closely 
with the preceding ■ and, finally Leverrier found by researches 
on the disturbances of the orbits of two of the planets. Mercury 
and Mars, a result consistent with the others. It is believed 
that by the observations of the recent transit of Yenus a result 
will be obtained which will certainly differ not more than a 
hundredth of a second from the truth. This will give us what 
we have never had before, — a correctly measured base-line 
for the solar system, as well as for cosmical measures beyond 
its limits. 
But for our present purpose the discoveries made by means ’ 
of spectroscopy are far more important as showing the unity 
of structure in the members of the solar system. I need not 
on this occasion show you the way in which the various ele- 
ments existing in the incandescent atmosphere of the sun are 
analyzed by the spectroscope ; it is sufficient to state that at 
least twenty of the sixty-four chemical elements which exist in 
the earth are found in a state of incandescent vapour in the 
sun's atmosphere. The fact that the greater number of our 
chemical elements (including the precious metals) are not 
found, is not conclusive with regard to their existence or non- 
existence in the sun. It may be that their greater density 
does not allow of their vaporization. But the only fact which 
concerns us at present is the similarity of the structure and of 
the constituent elements of the sun and the earth, and this is 
abundantly proved. 
Other facts deduced recently from the study of the sun, 
though of great scientific interest and importance, do not con- 
cern us much from the religious point of view. Thus the 
periodicity of frequency of the solar spots, which goes through 
its cycle in about eleven years, is practically of great import- 
ance, and opens a great field for speculation and research. It 
has, undoubtedly, an effect on climate, and I have myself 
traced its effect in producing a well-marked change of 
direction of the wind having the same cycle. The solar 
prominences likewise which are now observed as regularly 
and with as much care as any other phenomena, thanks to 
the discoveries of Mr. Lockyer and M. Janssen, indicate dis- 
turbances in the solar atmosphere of enormous magnitude, 
and may be of great practical impoi’tancc, but they otfer no 
occasion for further remark. The same may be said of the 
corona or broad ring of light seen during solar eclipses, 
which is proved to belong to the sun, and gives some indica- 
tion of dense nebulous matter in his immediate vicinity. 
