But what Idea of Distance can you receive from this sort of Estimation, where Numbers arise so very high. I own to you mine are soon quite lost by this Method of counting, either, Distances or Duration. I believe few People can range their Ideas with such Perspicuity, as to arrive at any adequate Notion of any Number above a thousand. To give you therefore a clearer Idea of Distance, and impress the Proportions of Space more strongly and fully in your Mind, let us suppose the Body of the Sun, as I have said before, to be represented by the Dome of St. _Paul's_; in such Proportion a spherical Body eighteen Inches Diameter, moving at _Mary-le-bone_, will justly represent the Earth, and another of five Inches Diameter, describing a Circle of forty-five Feet and a half Radius round it, will represent the Orbit and Globe of the Moon. A Body at the _Tower_ of 9,7 Inches, will represent _Mercury_; and one of 17,9 Inches at St. _James's_ Palace will represent the Planet _Venus_; _Mars_ may be supposed at a Distance, like that of _Kensington_ or _Greenwich_, 10 Inches Diameter: _Jupiter_, imagined to be at _Hampton-Court_, or _Dartford_ in _Kent_; and _Saturn_, at _Cliefden_, or near _Chelmsford_: The first represented by a Globe 15 Foot 4 Inches Diameter, the latter by one of 11 Feet ¾ Inches and his Ring four Feet broad: These would all naturally represent the planetary Bodies of our System in their proper Orbits and proportional Magnitudes, as moving round the Cupola of St. _Paul's_, as their common Center the Sun. And preserving the same natural Scale, the Aphelion of the first Comet would be about _Bury_, the second at _Bristol_, and the third near the City of _Edinburgh_. But if you will take into your Idea one of the nearest Stars; instead of the Dome of St. _Paul's_, you must suppose the Sun to be represented by the gilt Ball upon the Top of it, and then will another such upon the Top of St. _Peter's_ at _Rome_ represent one of the nearest Stars. The whole System exhibited in the above Proportion, would be nearly as follows: Diameter of the Sun 145 Feet. _Saturn_ 11,587, his Ring 27,54, its Breadth 4. _Jupiter_, 15,39. _Mars_, 10,15 Inches. the Earth, 18,125. _Venus_, 17,98 _Mercury_, 9,715 and the Moon, 4,93 [AU]Distance of _Saturn_ from the Sun, 27 Miles, and 1700 Yards. _Jupiter_, 15 Miles, and 458 Yards. _Mars_, 4 Miles, and 751 Yards. the Earth, 2 Miles, and 1632 Yards. _Venus_, 2 Miles, and 217 Yards. _Mercury_, 1 Mile, and 267 Yards. and of the Moon, from us, 45 Yards and a half. [Footnote AU: Of the Satellites of _Saturn_ in the above Proportion.