

TRANSACTIONS OF THE SECTIONS. 93 
ference between these objects as seen in the telescopes of Lord Rosse (even the three- 
feet) and those of previous observers, how desirable it was that a complete review 
of the nebulze should be made without loss of time. Even now much labour and 
talent were expended in theorizing on the imperfect data given by instruments, which 
though matchless in their time have now been surpassed. Among others he di- 
rected the notice of the Section to H, 604, where the two clusters and the associated 
epyals are projected into ellipses; and to H, 2205, in which the long-resolved ray, being 
the most intense, was alone seen by Herschel, but the magnificent spirals and their 
central stars escaped him. M. 65, H. 857, appear to be helices seen obliquely. 
But the most curious one is M, 33, of which the centre is a triple star disposed as 
an equilateral triangle among a mass of smaller, from which proceed eight or nine 
spirals ; and round all is an enormous nebula, in which howeyer no spiral character 
had yet been traced. 
There were several examples of another singular system, nebulz streaked with 
dark bands, such as Bond discoyered in the great nebula of Andromeda. H. 399, a 
wisp; H, 1393, a long ray of most marvellous appearance; H, 218, an oblique with 
sixteen or seyenteen dark transverse stripes; and H. 315, haying in the nebula a 
cluster nearly insulated by offsets from the broad curved dark band, are among the 
most surprising. But the number of these curious objects was so great that 
time would only permit him to invite attention to H. 1052 and 1053, where the 
cause of spirality had been interrupted by some other forces that bent the system at 
a right angle and drew the nebula into a straight ray; to H. 444, a double resolved 
nebula inclosed in a large and faint oval ring; and above all to M. 27, the “ Dumb 
Bell” nebula as shown by the six-feet, with its brilliant two clusters of comparatively 
large stars, its dark bands and the faint rings which surround it differing even more 
from the picture of the three-feet than that does from the figure of Herschel, 
In the name of the Section he thanked Lord Rosse, not merely for the pleasure 
which they received from the sight of these wonders, but for the unremitted and 
precious gifts which he was conferring on astronomy. Would he also increase their 
gratitude by mentioning any improvements which he might have lately made in the 
methods of suspending these large specule in their tubes or in the process of polish- 
ing, the latter with reference to the possibility of its being practised with success by 
persons who had not the long experience and mechanical knowledge of his Lordship ? 
Lord Rosse adyerted to the peculiar conditions of equilibrium which must prevail 
in these systems, or rather to the forces which are required to produce the peculiar 
constitution which they indicate, and pointed out the difficulties of such an investi- 
gation. It could however not be undertaken with advantage till we possess a much 
more extended collection of data, to which he would contribute to the utmost of his 
power. These drawings were based on measures carefully taken with a bar-micro- 
meter (the only one available in such cases), and he believed they might be trusted. 
He had already described the improvement effected by supporting the speculum on 
its lever by eighty-one balls, and mentioned the striking fact, that with a speculum 
weighing 32 tons a slight pressure of the hand would deform for a time the image 
of a star. He had since effected a further improvement by supporting the edge of 
the speculum in a hoop mounted in jimmals. As to polishing, he had recently made 
many experiments with 3-feet specula in reference to the object of Dr. Robinson’s 
question, and in particular had found, that, by increasing the speed of the second ex- 
centric in his machine, the process was rendered so much more certain, that desiring 
one of his workmen, a smith, to perform the whole process without any superintend- 
ence on his part, he produced a speculum, not perhaps absolutely perfect, but capable 
of doing excellent work. He had no doubt that any person of ordinary mechanical 
capacity would be able to do as much with a little instruction, and he would be most 
willing to give that instruction to any observer that might be placed in charge of a 
large reflector. : 

