726 
Proceedings of the Royal Society 
stem-like base is a hypertrophy due to the irregular surface the 
colony was attached to, and that, therefore, this species cannot with 
certainty be separated from Clavelina. 
Simon’s Bay ; 10 to 20 fathoms. 
7. Description of New Astronomical Tables for the Computa- 
tion of Anomalies. By Mr Edward Sang. 
(Abstract.) 
The planets move round the sun in ellipses, in such a manner 
that the radii vectores describe areas proportional to the times. 
Now, by means of parallel lines, we can always project an ellipse 
upon a plane surface so as to make the projection circular, and thus 
we have to consider the motion of a point in the circumference of a 
circle, describing round an excentric point areas proportional to the 
times. If we take S for the excentric point, that is for the projection 
of the sun, and suppose Q to be the projection of the planet’s place, 
the area ASQ is proportional to the time elapsed since the perihelion 
passage. The angle AOQ is called, very inappropriately, the ex- 
centric anomaly ; I prefer to call it the angle of position. If we 
suppose a point M to move uniformly along the circumference, 
with the periodic time of the planet, and to have reached M when 
the actual projection of the 
planet is at Q, it is clear that 
the sector AOM must be 
equivalent to the area ASQ. 
The angle AOM is the mean 
anomaly. 
Having drawn ESE per- 
pendicular to the diameter 
ASOa, join QE and QF ; then 
it is evident that the surface 
EQFA is halved by the com- 
pound line ASQ ; wherefore 
the area ASQ passed over by the radius vector is half the sum or 
half the difference of the circular segments QAF and QE, according 
as Q lies beyond AE or within it. 
Denoting the arc AE by e, and the arc of position AQ hy p, and 
