1918.] The N.Z. Journal of Science and Technology 169 
vertical line through the date until it meets the graph of a planet’s motion. 
If the point of intersection is above the Sun’s line the planet will be visible 
in the evening sky. If it is near one of the dotted lines AB or GB the 
planet is nearly in opposition, and will rise about sunset and remain visible 
d 
o 
Q 
> 
o 
Z 
CJ 
o 
c. 
<u 
C/3 
a 
< 
o 
5 
>> 
£ 
C. 
< 
'V 
GO 
rH 
m 
-±=> 
o 
3 
c3 
© 
•n 
s3 
c6 
S3 
S 
m 
© 
A 
o 
w 
S3 
o 
• r-* 
m 
S3 
<D 
O 
cc 
<3 
A 
QC 
d 
M 
fa 
all night. If it is near the line CD the planet will be near the meridian 
at sunset and will set at midnight; but if it is near the line EF it will be 
seen only from midnight till dawn. 
The point where any two graphs meet indicates a time when the two 
bodies are in conjunction. For example, by following the graph of Venus 
we see that she is in conjunction with Uranus about January 1, February 1, 
and April 2 ; with the Sun on February 9 and November 23 ; with Mercury 
