NEWS FROM THE MOON. 22$ 



the vaporisation of a frozen atmosphere, and of frozen 

 oceans. The simple fact, however, that Lord Kosse's 

 experiments prove that the full moon is greatly heated, 

 disposes at once of the fanciful theory we have been 

 considering. For a frozen lunar atmosphere could not 

 be heated beyond the point (corresponding to an 

 exceeding cold) where it becomes gaseous, until the 

 whole of- it had assumed this form ; and after that, the 

 water under the atmosphere could not be heated above 

 boiling heat without turning altogether into steam. 

 Now of two things one. The boiling heat would be 

 either high or low. If high that would imply con- 

 siderable atmospheric pressure, and we could not but 

 recognise an atmosphere producing such pressure ; if 

 lowj then the degree of heat to which the moon is 

 raised, as Lord Eosse's experiments show,* remains 

 altogether inexplicable. 



There is another strange theory in explanation of 

 the absence of water and air in the moon, due to 

 Dr. Frankland. According to this theory, the oceans 

 and atmosphere which once existed on the moon have 

 now withdrawn into the moon's interior. c If water at 

 one time existed on the surface of the moon,' says 

 Frankland, ' whither has it disappeared ? If we assume, 

 in accordance with the nebular hypothesis, that the 

 portions of matter composing respectively the earth 



* Lord Eosse separates the effect of reflected sun heat from that heat 

 which the moon emits as a warmed body. We do not explain here the 

 principles which render it possible to distinguish between these two 

 forms of heat ; but their sufficiency is altogether beyond question. 



