xvii REPORT—1850. 
such good service in our own, and has thus enriched astronomy with 1600 
more equally well observed, but beyond the reach of European astronomers. 
“ Yet powerful as those instruments were, a much nearer approach to the 
extreme limit of useful optical power has been made by Lord Rosse: it was . 
therefore to be expected that his telescope would add considerably to our 
knowledge of the Nebule, and this has been fully realized. It was in fact a 
communication of some results obtained by him which directed the attention 
of the British Association to this subject, and excited a desire of having the 
same work performed for the southern sky which he is accomplishing in our 
own. That work implies a minute re-examination of at least all the brighter 
Nebule of Sir John Herschel’s catalogues ; embodied in drawings, based on 
micrometer measures, and so correct that each of them may be referred to 
without doubt by future astronomers as an authentic record of the original’s 
appearance at a given epoch. Of such drawings we at present possess very 
few: most of the sketches given by the Herschels are stated by them to be 
made merely by eye; and even those that were more accurately taken by 
them are found to require amendment when compared with the appearances 
in more powerful telescopes. 
“A task of this kind can only be wrought out by severe and long-con- 
tinued labour ; and the instrumental means required are such as very few in- 
dividuals can obtain by their private resources. Even in Europe there are 
but three telescopes known to exist which are capable of making any great 
additions to the discoveries of the Herschels; and those three are in the 
British Islands. This field of research is therefore still exclusively our own; 
and I trust your Lordship will share my feeling, that the nation’s honour will 
be sullied if we let it be preoccupied in its most interesting portion by the 
energy and liberality of any other people. 
“In submitting to your Lordship this request of the British Association, I 
feel it my duty to give with it some approximative estimate of the sum which 
might be required for its accomplishment. 
“ First, as to the instrument: it has been proved by the experience of Lord 
Rosse, Mr. Lassels and others, that one of sufficient power can be constructed 
with certainty and at no overwhelming cost. I have made inquiries of an 
artist (with whose abilities in this line I am practically aequainted), and have 
come to the conclusion that a telescope similar to the smaller of Lord Rosse’s 
8 feet aperture and 27 feet focal length might be constructed for £2000. 
This would include an equatorial mounting ; clock-work to make the telescope 
travel with a star; apparatus for supporting the observer ; and a machine for 
polishing the speculum, when that operation may be required. If a second 
speculum were supplied (which seems almost essential in case of accident), it 
would add about £500 more. Of course some latitude must be allowed in 
this, but it need not be wide; the work could not be completed in Jess than 
a year, possibly would employ two. As telescopes so gigantic are erected in 
the open air, no outlay would be necessary for any building except the 
Observer's dwelling. ἊΝ 
“ὁ Secondly, the Observer need not possess very high mathematical attains _ 
ments; acute sight, and skill as a draughtsman, being his most important re- 
quisites; and his staff need not consist of more than two or three labourers, 
one of whom should be a practical mechanic. 
“11 am quite aware that there are some persons who will consider the sum 
that I have named above, and the moderate annual expenditure which would 
be required for a few years, a very unprofitable waste of public money. I 
feel also assured that your Lordship is not of their number; no man can be — 
who has ever drunk of the fountain of knowledge, or added to the domain of | 
