VII. Observations of the Places of the Georgian 

 Planet, made at Edinburgh with an Equatoreal Jtijlrument. 

 By John ROBISON, A. M. F. R. S. Edin. aud Profeffor 

 of Natural Philofophy in the TJniverfity of Edinburgh. 



{Read by the Author^ March 7. 1787.] 



Hence it may be deduced, (by following the method de- 

 fcribed in a paper, formerly read to this Society*) that the planet 

 was in oppofition January 13''. 04*. 56' M. T. Greenwich, in 

 longitude, 2>' ^.S"- 32'. 24" from the mean equinox, with 

 — °. 30'. 38" north heliocentric latitude. 



The error of the theory in longitude is nearly +5", and in 

 latitude nearly — 1 8". 



I attribute this error in latitude to the different manner 

 in which I obferved the declinations. I formerly obferved the 

 difference of declination between the planet and fixed ftar by 

 means of a common micrometer. But I was obliged to fubfli- 

 tute Dr Bradley's rhombus for my micrometer, which had re- 

 ceived an injury which I could not get repaired in time. If 

 this be allowed, the error in longitude will be diminifhed 

 nearly 2". 



My telefcope has an achromatic objedl glafs of 44 inches focal 

 diftance, magnifies 1 9^ times, and takes in a diflindl field of 



92'. 



* Tranfaaionsof the Royal Society of Edin. Vol.1. N" XI. Phyf. CI. 



