84 IN STARRY REALMS. 



hundred and forty miles. It follows that no object can be 

 visible on the moon even from our greatest observatories 

 unless it be large enough and distinct enough to be visible 

 with the unaided eye at that same distance of two hundred 

 and forty miles. 



This at once shows that we need not expect to see 

 any objects on the moon, even with our best telescopes, 

 unless those objects have dimensions that must be veri- 

 tably colossal. An elephant could hardly be seen, even 

 under the most favourable circumstances, at a distance 

 of more than a couple of miles, so that the biggest ele- 

 phant would be utterly invisible on the moon, unless 

 our telescopes were a hundred times more powerful than 

 any instrument that has ever yet been constructed. In 

 fact, with our present appliances, no object would be 

 visible on our satellite unless it were as large as some great 

 building like a cathedral or town-hall. The loftiest trees 

 could not be discerned if they grew on the moon, though 

 it must be admitted that were there vast forests on our 

 satellite, which shed their leaves periodically, the varying 

 hues in the different seasons would doubtless be detected. 

 But phenomena of this kind have never been fully estab- 

 lished, and hence we are obliged to conclude that, so far 

 as direct telescopic observation goes, the evidence as to 

 the existence of organic life on our satellite must be 

 esteemed entirely negative. 



There is, however, another way in which the question 

 can be studied, and which will suffice to show that, in all 

 probability, life of evt,ry type with which we are ac- 

 quainted must be almost certainly absent from the moon. 

 Every kind of life, whether animal or vegetable, requires 



