of Edinburgh, Session 1880-81. 
97 
William Lassell. By the Ilev. T. R. Robinson, D.D., E.R.S., 
Armagh Observatory. 
William Lassell belonged to a class of men which is (as far as 
I know), peculiar to these Islands ; men who, while carrying on 
commercial or manufacturing business with energy and success, join 
to it higher pursuits, seeking recreation in devotion to some depart- 
ment of science, some doing this at much sacrifice of time and 
labour, and frequently at a princely expenditure of money, and often 
rewarded by results of the highest importance to knowledge. Such 
persons deserve all honour, and of such none more than the subject 
of this notice, whose services to what may be called Optical 
Astronomy were so great as fairly to entitle him to rank with Sir 
William Herschel and Lord Rosse. He first became known to the 
astronomical world in 1840 by his description of a Newtonian of 
nine inches aperture, which he mounted on an Equatorial of his 
own contrivance at his residence near Liverpool. The specula were 
polished by hand, but must have been of surpassing light and 
definition, for he saw with it (having no previous knowledge of the 
star’s existence) the sixth star of the trapezium in Orion, which 
the elder Struvk had failed to detect with the renowned Dorpat 
Achromatic nine and half inches aperture ! 
With this instrument he did good work for some years, till the 
success of the late Lord Rosse, in figuring specula of very large size 
by machinery, made him wish for a larger telescope. After 
visiting Parsonstown and studying Lord Rosse’s work, he con- 
structed a two feet Newtonian by processes which he has described 
in the “Astronomical Society’s Memoirs” (vol. xviii.) with singular 
precision and clearness of detail. He was far from copying Lord 
Rosse’s method (and his mode of forming the alloy was objection- 
able, when arsenic was used, even dangerous), and although his 
machine was found by himself and also by Warren Be La Rue to 
be imperfect, yet his minute observation of even the most trifling 
facts and his intelligent appreciation of their bearings on the result, 
enabled him to obtain in this instance also an admirable telescope ; 
though ultimately he used another machine whose action nearly 
resembled Lord Rosse’s. 
This telescope showed seven stars in the Orion trapezium, which 
