System of the Universe. 269 



Trine is an aspect of two planets when they are a hun- 

 dred and twenty degrees distant from each other, and in 

 an ephemeris it is denoted by A. In like manner quartile, 

 marked D , is when two heavenly bodies are 90 asunder 

 in longitude ; opposition^ marked , when they are 180 

 asunder ; and conjunction, marked , when two heavenly 

 bodies have the same longitude. Thus at the time of new 

 moon, the sun and moon are in <J ; at the time of full 

 moon they are in g; and in the first and last quarters they 

 are in n or quartile aspect. These aspects for all the 

 planets are shown in Partridge's Almanac. 



The diurnal Parallax of a heavenly body is the angular 

 distance between the places of the body, when referred to 

 the heavens, as seen from the centre and the surface of the 

 earth j or it is the angle^which the earth's radius would 

 subtend at the heavenly body. 



The annual Parallax, or the parallax of the earth's or- 

 bit, is the angular distance between the different places of 

 the body as seen from opposite points of the earth's orbit. 



Apogt is that point of the orbit of a planet or the ima- 

 ginary orbit of the sun which is farthest from the earth. 



Perigt is that point in the orbit of a planet, &c. when 

 it is nearest to the earth. 



Aphelion is the point of an orbit most distant from the 

 sun. 



Perihelion is that point of an orbit, wheiher planetary 

 or cometarv, which is nearest the sun. 



