TRANSACTIONS OF THE SECTIONS. 15 
the ellipse, gives a mean of 26"-2 for the transverse, and 166 for the conjugate 
axis. 
The accompanying drawing has not 
been at all corrected by these measures, ———~_ 
but is the result of several sketches made * 
during different observations, and is a oa 
faithful transcript of the appearance of 
the nebula to my eye, when most favour- 
ably seen. 
The object is, as may be supposed, one of extreme difficulty, requiring in the 
highest degree the combination of light and definition in the telescope, and a fa- 
yourable state of atmosphere,—which will further appear when I state that it was 
not until I was favoured with an unusually fine night, and had applied a power of 
1480, that the whole of the details were brought out. 
I confess I have been greatly impressed by the revelation of this most wonderful 
object, situated on what perhaps we may consider as the very confines of the acces- 
sible or recognizable part of the universe, affording ground for the inference that 
more gorgeous systems exist beyond our view than any we have become acquainted 
with. Tam, &c., W. LasseLt, 
Observed R.A. and N.P.D. of Comet II. 1862. 
By the Rey. R. Mary, M.A., FBS. 
This paper gave the results of observations of the comet from August 5 to August 
29, on ten nights. It was observed on the meridian with the Carrington transit- 
circle on August 7 and 9, and off the meridian with the heliometer, used as an or- 
dinary equatorial, on August 5, 7, 9, 14, 18, 19, 22, 23, 25, and 29. The observations 
have bccn rigorously reduced, and all necessary corrections for refraction, parallax, 
&e. have been applied. The assumed mean places of the companion stars for 1862, 
January 1, taken mainly from the ‘ Radcliffe Catalogue of Circumpolar Stars,’ were 
also given. 
On the Dimensions and Ellipticity of Mars. 
By the Rev. R. Mary, M.A., PRS, 
This paper gave the results of seven sets of measures of the disk of Mars, made 
for the determination of his ellipticity with the heliometer, by the method of contact 
of limbs of the two images formed by the half-object-glasses. The power used was 
300, which is found by experience to be very suitable for such measures. The 
direction of the polar diameter was determined by a well-defined circular white cap 
near the southern limb, the centre of which was assumed to be coincident with the 
South Pole. The directions, separately estimated, of the polar and equatorial 
diameters agreed well on separate evenings, their difference never deviating much 
from 90°, thus proving the precision of the estimations. The measured diameters 
haye been corrected for defect of illumination. 
The following are the results of the measures :— 
Polar diam. Equat. diam. Ellipticity. 
uu “ 
1862, Sept. 18 21-844 22386 ar 
pe MIS” yy eRadb 22-986 = 
* 22 22-704. 22-974 a 
ae 22-138 22-911 as 
F aiktelh 22-551 23-106 s 
eo aan 22-519 23-125 He 
pb 80 22-896 23-012 eS 
198°4 
Mr. Main drew particular attention to the difference in the degrees of consistency 
in the results for the polar and for the equatorial diameter, the latter agreeing sur- 
