28 HG REPORT—1858. 
if we add to them Neptune, making 12 in all, the perihelia of 10 of these are found 
between 0° and 180°; and of the nodes of the 11, none are in the semicircle 180° to 
360°. This Table also exhibits these somewhat singular facts, that, adding to the 
first 12 those subsequently discovered in groups of 10, the number of perihelia and 
number of ascending nodes in each semicircle are almost exactly similar. I would 
also observe, that it may be seen, by the diagrams of heliocentric longitude, that the 
perihelia and ascending nodes are frequently grouped together in a remarkable man- 
ner. I deal now entirely with facts: causes I leave to the more learned in celestial 
dynamics. 
Including Neptune from the First. 
L. Ps. 0° to 180° 180° to 360°, 
When 12 Planets there were ..... 10 ...... 2 
REL Mae wisticne. +dm fie nasise 1 a a 5 
Se OULO me i audesiete aadea AS Ta ROS 3 A 
OATES Bib pasven set cuendns DO coseeee 12 
he NOI A aboatesel, ikea earess by eee 15 
ON CAEEON 2 teense ae ci sas eee AD. whe ants 19 
2 0° to 180° 180° to 360° 
When 11 Planets there were ...... i. coctes * 0 
21 ditto annie Tek Rae 3 
YL UEEO ) ac winabay Soe 115 jl 6 
Ae TEL y cidanna ee (Us 11 
AIC we eice tad sk oakcs ph A ne Sasa 15 
Pe GItl), oe tin ceacie. . 2. nee ean 1D tenedek. Aes 
Donati’s Comet.— Extracts from Letters received by ¥:. J. Cooper, M.P., 
from Mr. A. Granam, MRLA. 
‘“‘ Markree Observatory, Sept. 20. 
««T hoped to be able to give you ere now some interesting details of this glorious 
comet, but I was arrested in my calculations by a curious result in my observation 
of September 14,—the only really good one which the weather permitted me to make 
up to that time. Both the compared stars occur in Bessel’s zone 359. One of the 
two is also in Lalande, No. 21775 (Catalogue). The mean right ascensions from the 
two catalogues differ by 12 seconds in time! There were two wires taken by both 
observers, and I have carefully looked over the reductions. I even got C. Robertson 
(second assistant) to ascertain the mean places, and he brought out exactly the same 
resultas I. On Saturday evening (18th) the comet presented rather a striking ap- 
pearance in the nucleus and coma. The part to the right-hand side of the tail was 
brighter than the left. I directed the attention of C. Robertson to this circumstance, 
to make sure that my eyes did not deceive me; and his impression precisely accorded 
with mine. Now it did not strike meat the time that this was the side next the sun, 
and that the phenomenon indicated a phase such as would be caused by light reflected 
from the surface. The appearance of the tail was exactly such as would be presented 
by a hollow conoid of thin vapour under the circumstances. It will be interesting if 
other observers confirm this remark.” 
September 22. ‘‘ We got satisfactory observations of the comet on Monday and 
Tuesday nights. The note in the observing book for Monday the 20th is as fol- 
lows :—The south side of the nucleus faded off gradually into the coma without 
any defined boundary line. The north and north-east pretty well defined. The 
nucleus seemed to be stretched out westward at an angle of about 120° with the 
tail, giving a rough idea of a cusp. There was a similar appearance towards the 
east, in continuation of the line, but not so well marked. Southward of a line 
touching the nucleus on the north side, and making an angle of about 60° with the 
axis of the tail on the east side, the light was decidedly stronger than on the other 
side of this line. The entire impressed us with some such idea as a view of Venus 
would give when slightly gibbous, and when seen very near the horizon, with bad 
definition. The light of the tail was pretty uniform throughout the entire breadth 
for about twice the diameter of the nucleus northward. Thence it parted into two 
