COMMEMORATION MEETING. 



171 



conclusions of science. The great man of science whom France 

 lost a few years ago, Poincare, cousin of the President of 

 the French Kepublic, said, " There are no true hypotheses in 

 science ; there are convenient hypotheses, and that hypothesis 

 is the most convenient which best accords with the facts." 

 There is no moral or spiritual superiority in holding one 

 scientific hypothesis rather than another. The man who 

 follows Galileo is not made thereby a better man than the 

 man who follows Ptolemy: he may be better instructed or of 

 better intelligence, but his superior knowledge does not bring 

 him nearer to the Divine Image. 



Is there then no advantage, for those special purposes which 

 tin 4 Victoria Institute has in view, in the lectures and addresses 

 which we have had from time to time from such leading 

 astronomers as those whom I have mentioned ? I think the 

 advantage has been great. The progress of astronomy during 

 the last sixty years has been so remarkable, so revolutionary, 

 that it requires a very serious effort to realize the conditions 

 that existed before. Sixty years ago, astronomy was limited to 

 the repeated determination of the apparent positions of sun, 

 moon and stars and planets, and by such repeated observations 

 their movements were ascertained. Questions as to the 

 composition and physical condition of the heavenly bodies 

 were barely entertained. 



How great is the difference now ! The application of the 

 spectroscope to the analysis of the light of the sun and of the 

 stars founded what may be called Celestial Chemistry, and we 

 have learnt to recognize many elements familiar to us here 

 as existing not only in the sun, but in the distant stars. 

 We have ascertained the temperature of the sun's surface to 

 be about 12,000° Fahr., so that metals like iron, here normally 

 solid, there always exist as glowing gases. The spectroscope 

 has further enabled us to group the stars according to their 

 temperature conditions, and they have been arranged in order 

 of stellar evolution. 



It is worth while noting that the word " evolution," which is 

 so prominent in the philosophy of Herbert Spencer, has many 

 different and independent meanings which are not as carefully 

 distinguished as they ought to be. Stellar evolution practically 

 means that a celestial body in the process of cooling undergoes 

 changes of condition which are evidenced in its spectrum. 

 Organic evolution, so intimately connected with the name of 

 Charles Darwin, differs in its conceptions so widely from the 

 ideas involved in stellar evolution that an astronomer and a 



