CONDITIONS OF HABTTABILITY OF A PLANET. 



97 



and I have been much disappointed that he has rather taken the 

 other line, and argued that there are very few, if any, inhabited 

 worlds other than our own. Surely all the millions of stars which 

 the telescope shows us were not created without some purpose ; may 

 they not have planets revolving round them that we cannot see and 

 •of which we knew nothing And of the planets in the solar system, 

 may there not be forms of life quite unlike those with which we are 

 familiar that would flourish under such conditions that they offer 1 

 Why should we think that water is the only liquid that can support 

 life? 



A Member asked : Might not life be possible on Mars near the 

 edge of the polar caps since, when the ice is melting, there would be 

 abundance of water there ? 



Mr. Schwartz said : Mr. Maunder has given us an interesting- 

 paper but I fear that he has taken a rather prejudiced view of the 

 question. Mr. Maunder says on the first page that all men would 

 greatly delight to be able to recognize the presence of races similar 

 to our own upon other worlds ; I rather think myself that the reverse 

 is the case. Then, again, I think Mr. Maunder was quite un- 

 warranted in assuming that we know all the elements that exist. 

 Up to a very few years ago we knew nothing of helium beyond 

 the bright line which it showed in the solar chromosphere ; now it 

 has been discovered on the Earth. Nearly one-third of the dark 

 lines of the solar spectrum are not yet assigned to any element 

 known to us on the Earth, and several terrestrial elements have not 

 yet been identified in the sun. 



Mr. D. Howard said : Mr. Maunder's paper is specially interest- 

 ing as an example of accurate scientific thought applied to a question 

 generally discussed only from a popular point of view. He has 

 shown us exactly what the conditions must be on Mars and they 

 certainly are incompatible with organic life. 



The history of the canals is a very curious one and shows the 

 difficulty of accurate observation even for skilled observers. I am 

 afraid we must still be content to doubt what the markings on Mars 

 are and still more what they are caused by, but if highly organized 

 life is impossible on Mars they cannot be the result of the labours of 

 Martians. 



Let us always beware of " must he's." " There must be inhabitants 

 of the planets, or if not what use are they." 



B 



