( 576 ) 
ignorant of s the Medium it felf may bealwaies lumi- 
nous after the manner of our Ignes fatui. The Con- 
cave Arches may in feveral places fhine with fuch a fub- 
ftance as inverts the Surface of the Sun 5 nor can we, 
without a boldnefs unbecoming a Philofopher, adventure 
to aflert the impolfibility of peculiar Luminaries be- 
low, of which we have no fort of Idea. \ amfurethe 
Poets Virgil and Claudian have gone before me in this 
Thought, inlightning their Elyfian Fields with Sun and 
Stars proper to thofe infernal, or rather internal, Regions. 
Virg.yEneid.6. 
Largior hie compos dther © famine veftit 
Purpureo$ Solemque [mm fuaSideranorunt. 
And Claudian lib. x. De Raptu Proferpin*. 
Amijfum necrede diem, funt altera nobis 
Sidera 9 funt cries alii, lumenque videbis 
Purius 9 Elyfiumque magis mirabere Solem. 
And though this be not to be efteemedas an Argument, 
yet I may take the liberty I fee others do, to quote die 
Poets when it makes for my purpofe. 
Laftly, To explain yet farther what I mean, I have 
adventured to ad joy n the following Scheme, wherein 
the Earth is represented by the outward Circle, and the 
three inward Circles are made nearly proportionable to 
the Magnitudes of the Planets Venus, Mars and Mer- 
cury, all which may be included within this Globe of 
Earth, and all the Arches more than fufBciently ftrong 
to bear their weight. The Concave of each Arch, which 
is fhaded differently from the reft, I fuppofe to be made 
up of Magnetical Matter ; and the whole to turn about 
the fame common Axis p, p. only with this difference, 
that the Outer Sphere uill moves fomewhat fafter than 
