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VOL. XVII.] PHILOSOPHICAL, TRANSACTIONS. 4^^ 



the earth, as Q to 5, why may we not reasonably suppose the moon, being a 

 small body and a secondary planet, to be solid earth, water, and stone, and this 

 globe to consist of the same materials, only four ninths thereof to be cavity, 

 within and between the internal spheres. 



To those that shall inquire of what use these included globes can be, it must 

 be allowed, that they can be of very little service to the inhabitants of this out- 

 ward world, nor can the sun be serviceable to them, either with his light or 

 heat. But since it is now taken for granted that the earth is one of the planets 

 and that they all are with reason supposed habitable, though we are not able to 

 define by what sort of animals; and since we see all the parts of the creation 

 abound with animate beings, as the air with birds and flies, the water with the 

 numerous varieties of fish, and the very earth with reptiles of so many Sorts ; 

 all whose ways of living would be to us incredible, did not daily experience 

 teach us ; why then should we think it strange that the prodigious mass of 

 matter, of which this globe consists, should be capable of some other improve- 

 ments, than barely to serve to support its surface ? Why may not we rather 

 suppose that the exceeding small quantity of solid matter, in respect of the 

 fluid ether, is so disposed by the Almighty wisdom, as to yield as great a sur- 

 face for the use of living creatures, as can consist with the conveniency and 

 security of the whole ? 



But still it may be said, that without light there can be no living, and there- 

 fore all this apparatus of our inward globes must be useless: to this I answer, 

 that there are many ways of producing light, which we are wholly ignorant of; 

 the medium itself may be always luminous, after the manner of our ignes fatui. 

 The concave arches may in several places shine with such a substance, as invests 

 the surface of the sun ; nor can we, without a boldness unbecoming a philoso- 

 pher, adventure to assert the impossibility of peculiar luminaries below, of which 

 we have no sort of idea. 



Lastly, to explain yet farther what I mean, I have adventured to add the fol- 

 lowing scheme, fig. 18, pi. U, where the earth is represented by the outward 

 circle, and the three inner circles are made nearly proportionable to the magni- 

 tudes of the planets Venus, Mars, and Mercury, all which may be included 

 within this globe of the earth, and all the arches be more than sufficiently 

 strong to bear their weight. The concave of each arch, which is shad«i 

 differently from the rest, I suppose to be made up of niagnetical matter ; and 

 the whole to turn about the same common axis p p, only with this difference, 

 that the outer sphere still moves somewhat faster than the inner. Thus, the 

 diameter of the earth being about 80U0 English miles, I allow 500 miles for 

 the thickness of its shell, and another space of 500 miles for a medium be- 

 tween, capable of an immense atmosphere for the use of the globe of Venus : 



