SUN S DISTANCE FROM THR EARTH. 1 5 



this is done for both observations at ever}^ station ; and thus 

 he calculates what will be the difference of the duration of 

 the transit at different stations. All this is upon the supposi- 

 tion that the sun's horizontal equatoreal parallax has a certain 

 value, say ten seconds. If they agree, the sun's horizontal 

 parallax is ten seconds ; if not, the true value will be found 

 by this proportion : As the computed difference of durations 

 is to the observed difference of durations, so is the assumed 

 horizontal equatoreal parallax to the true horizontal equator- 

 eal parallax. 



" In this manner it was found that the sun's horizontal 

 equatoreal parallax when the Earth is at its mean distance is 

 eight seconds and six-tenths, very nearly, and this corres- 

 ponds to the distance which I have stated before of about 

 95,300,000 miles. 



"It was thought at the time of the observations in 1769 

 that the sun's distance was determined with all the accuracy 

 of which the method was capable. As previously stated, 

 however, more recent investigations have led to the conclusion 

 that the sun's distance so estimated to be too gi'eat by about 

 three millions of miles." 



The parallax is until further correction set down as 8.789", 

 eig-ht seconds and seven hundred and eighty-nine one-thous- 

 andths of a second. As the sun is nearer, the parallax is 

 greater, and vice versa. 



As judged by the concensus of many methods of compu- 

 tation, 92,975,500 miles seems to be the most nearly accurate 

 statement on record of the sun's distance from the Earth. 



