370 Notices of Scientific Works. [July 



safe to say that no beings at all resembling tliose which live on 

 earth could possibly exist. Again, that side of the moon which is 

 visible to us has, in all probability, neither atmosphere nor water, 

 and it is subjected to the unimpeded action of the sun's rays for 

 the space of fourteen days without intermission, a protracted tropical 

 day, which is followed by an Arctic night of equal duration. 

 Although there are grounds for believing that in past aeons our 

 satellite may have been the abode of life, it is hardly possible, for 

 the reasons named, that it can be so in our time. 



Again, there are circumstances from which it may reasonably be 

 inferred that even where it is legitimate to assume the existence of 

 living creatures on certain orbs, they must be constituted differently 

 from those we know on our globe. For example, an object which 

 on the earth's surface weighs 1 lb., weighs only 7 oz. on Mercury, 

 but the same object would weigh 2-J- lbs. on Jupiter ; so that a man 

 of 10 stone here would have to carry 25 stone on Jupiter, and only 

 4 st. 6 lbs. on Mercury ; and Mr. Proctor, if he had wished to 

 indulge his lively imagination more freely than he has done, might 

 have conceived of Mercury as an advanced planet, peopled by a 

 superior race of beings, who having a lighter weight to carry and 

 consequently less need for muscular exertion, would probably 

 require only one meal a day to compensate for physical waste, and 

 would therefore have more time and energy to devote to higher 

 occupations than mere nutrition. And, as already mentioned, the 

 additional weight which creatures would have to carry on Jupiter, 

 with its present size and density, suggests the idea of its containing 

 vast seas, that support Ichthyosaurs and their congeners. These 

 are, of course, speculations, like Mr. Proctor's ; but it may be as 

 well to mention that on all matters involving biological as well as 

 physical considerations, even speculators should be conversant with 

 the past history of life on our earth ; should be geologists and 

 palaeontologists as well as physical and astronomical observers. 

 The more we study Nature as a whole, the greater the need appears 

 for a school of thought which shall embrace all natural sciences. 



In regard to the condition and habitability of other spheres, one 

 consideration — for it is absurd in the present state of our knowledge 

 to talk of conclusioDs — seems to press itself upon us, namely, whether 

 smaller orbs, as the nearer planets (Mercury, Yenus, the Earth, 

 Mars), and the satellites in the Solar system, do not mean ad- 

 vanced life, or (as on our Moon) life already passed away ; and the 

 larger planets, and the Sun itself, retarded inorganic and organic 

 existence. 



Those who desire to be fully informed as to Mr. Proctor's views 

 on these matters must turn to his interesting pages ; but it may be 

 remarked here, that he believes the exterior planets to be what may 

 be called semi-solar in their character, not only receiving heat from 



