In So Many And Such Important Ways,

For It Is The Duty Of An Astronomer To Compose The History Of The Celestial Motions Through Careful And Expert Study.

I Therefore Took This Opportunity And Also Began To Consider The Possibility That The Earth Moved. Although It Seemed An Absurd Opinion, Nevertheless, Because I Knew That Others Before Me Had Been Granted The Liberty Of Imagining Whatever Circles They Wished To Represent The Phenomena Of The Stars, I Thought That I Likewise Would Readily Be Allowed To Test Whether, By Assuming Some Motion Of The Earth's, More Dependable Representations Than Theirs Could Be Found For The Revolutions Of The Heavenly Spheres.

Yet The Widespread Planetary Theories, Advanced By Ptolemy And Most Other Astronomers, Although Consistent With The Numerical Data, Seemed Likewise To Present No Small Difficulty. For These Theories Were Not Adequate Unless They Also Conceived Certain Equalizing Circles, Which Made The Planet Appear To Move At All Times With Uniform Velocity Neither On Its Deferent Sphere Nor About Its Own Epicycle's Center.

I Shall Now Recall To Mind That The Motion Of The Heavenly Bodies Is Circular, Since The Motion Appropriate To A Sphere Is Rotation In A Circle.

Of All Things Visible, The Highest Is The Heaven Of The Fixed Stars.