THE QUARTERLY 
JOURNAL OF SCIENCE. 
OCTOBER, 1868. 
I. DESCRIPTION OF THE GREAT SOUTHERN 
TELESCOPE. 
By Wim Crooxss, F.RS., &c. 
SEVERAL years ago the Government of Victoria voted the sum of 
5,0002. for the construction of a large equatorial telescope to be 
erected at Melbourne, for the observation of the nebule and mul- 
tiple stars of the Southern Hemisphere. 
The construction was entrusted to Mr. Grubb, F.RB.8., of Dublin, 
who stands in the first rank as an optical and telescopic engineer 
in the manufacture of instruments in which every step is required 
to be preceded by mathematical research. At the commencement 
of the present year the telescope was completed and examined by 
the Committee of the Royal Society who had superintended the 
work throughout. In a report recently communicated to the Royal 
Society, the Committee express their unanimous opinion that the 
equatorial is a masterpiece of engineering. 
Before this notice meets the reader’s eye, the telescope will pro- 
bably be on its way to Australia, and as it is beyond comparison the 
largest and most elaborate equatorial ever constructed, it seems due 
both to the constructor and to the importance of the instrument 
that a detailed account of it should appear in the ‘Quarterly 
Journal of Science.’ Through the kindness of my friend Mr. Grubb, 
who has placed at my disposal drawings, photographs, and ample 
descriptions of all parts of the instrument, I have ventured to 
undertake this office. 
The great Melbourne telescope is of the form known as the 
Cassegrainian reflector, and is mounted equatorially on what Mr. 
Grubb calls “the German system improved.” 
The mirrors, two being supplied in case of accident, are 4 feet 
in clear aperture, 44 inches thick, 30 ft. 6 m. in focus, and rest in 
VOL. V. ae 
