SCIENTIFIC TRANSACTIONS 
OF THE 
BOQ MAG IDWISIDIOIN SOC IIa, 
IL—OBSERVATIONS OF NEBULA! AND CLUSTERS OF STARS MADE 
WITH THE SIX-FOOT AND THREE-FOOT REFLECTORS AT BIRR 
CASTLE, FROM THE YEAR 1848 UP TO ABOUT THE YEAR 18°78. 
BY THE RIGHT HON. THE EARL OF ROSSE, D.C.L., F.R.S. Parrs 
1&2. Wire Puarses I. to IV. 
[Read, February 18, 1878. ] 
From time to time after the completion of the six-foot reflector at Parsonstown, my 
late father brought out papers on some of the nebule and clusters of stars observed 
with the three-foot and six-foot instruments, the last having been published in the 
Philosophical Transactions of the Royal Society of London, for 1861. Since that 
date no account (with the exception of a monograph on the great nebula in Orion) 
of the observations of nebulz, which have been, with a few interruptions, carried 
on up to the present time, has appeared. 
It had for some time seemed desirable that a continuation of the former series of 
observations should be published, but it was difficult to decide with what degree 
of fulness they should be given, or how far it might be of advantage to bring 
out also, at the same time, at greater length, those made prior to 1860, from which 
a “selection” only, as it is named in the title of the above-mentioned paper, had 
been transcribed. 
We found that a very full, almost word for word transcription of the observer’s 
original notes was desired by those working in the same department of astronomy, 
and as D’Arrest and others had adopted the course of giving, in their published works, 
every observation separately, we thought we could not do better than follow, to a 
certain length, in their footsteps, omitting, however, all observations clearly inferior 
through weather and other causes to those of the same object, made under 
manifestly better conditions ; also all notes which only stated that an object had 
been viewed, without giving any details of description, &c. The uniqueness of the 
six-foot instrument renders apology for taking this course less necessary, and on the 
whole we felt that there was a better chance of advancing the subject by giving 
the observer's own words, except where too great diffuseness rendered abbreviation 
necessary. 
TRANS, ROY. DUB. SOC., N.S. VOD. IL. 
