24 



earth. Thus, by the doctrine of parallaxes, when they are 

 sensible, we find the absolute distances of the heavenly bodies ; 

 and when they are even insensible, we obtain from them, a 

 sort of negative information, which determines, that bodies 

 so circumstanced, must, at least, in their remoteness, exceed 

 certain limits, which we can easily assign. For thus much 

 is certain, that as no one of the fixed stars has any sensible 

 parallax, the distance of the nearest of them must exceed 

 twice the distance of the earth from the sun, multiplied 

 by 206,264, a distance which will be more distinctly con- 

 ceived by actually so multiplying any of the distances given 

 in the table, than by a mere inspection of the product. The 

 product of such a multiplication, supposing the double dis- 

 ' tance of the earth from the sun to be in round numbers, I90 

 millions of miles, will consist of fourteen figures. This multi- 

 plier* xvill give nearly the same number of miles for the nearest 

 of the fixed stars, as may be deduced from the following 

 correct analogy, supposing the same diameter of the annual 

 orb, as above stated, and a parallax in the fixed star of one 

 second. 



As the tangent of V : radius : : 190 millions of miles : dis- 

 tance = to 391 9 1000000000 British miles ! 



* This multiplier is the seconds in an arch equal to Radius. 



FARTHER 



