An epitome of astronomy, with the new discoveries: including an account of the eidouranion, or transparent orrery / (invented by A. Walker) as lectured upon by his son, W. Walker.

  • Walker, A. (Adam), 1730 or 1731-1821
Date:
1800
Catalogue details

Licence: Public Domain Mark

Credit: An epitome of astronomy, with the new discoveries: including an account of the eidouranion, or transparent orrery / (invented by A. Walker) as lectured upon by his son, W. Walker. Source: Wellcome Collection.

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    of a pale colour, and much larger in its tele¬ scopic appearance than the fixed stars, being 100 times as large as the Earth, or 37,230 miles diameter, and, on a clear evening, is vi¬ sible to the naked eye. The Dr. has disco¬ vered six satellites to this planet, some of which are said to move retrograde. As fami¬ liarity is the principal design of this Treatise and Lecture, it may be useful to exhibit the distances of the planets from the Sun in the most concise form, and in numbers they will stand thus:—if the distance from the Sun of Mercury—Venus—Earth—Mars—Jupiter—Saturn-—Georgium Sidus is 4.will be7....10.15.....52.,.95....190 v or, if a body projected from the Suu should continue to fly at the rate of 480 miles per hour, (which is about the swiftness of a can¬ non-ball) it could reach the orbit of Mercury in 9 years, Venus in 16 years, the Earth in 23 years. Mars in 34 years, Jupiter in 118 years, Saturn in 216 years, and the Georgium Sidus in 432 years. These we consider as the regular bodies of our system 3 so regular, indeed, that every phenomenon respecting them is calculated for