362 Prof. C. Piazzi Smyth'*s Meteorological 



propriety of such a proposition as that of the great *' Southern 

 Beflector." We should rather inquire if any very decidedly superior 

 instrument can he made noAv, to the last employed for a similar 

 purpose. 



Then the decisive answer can be given, that instruments larger, 

 and cheaper, and better can be made now than at any former 

 period in the history of the reflecting telescope ; and when every 

 person who has had a hand in the making of the modern re- 

 flecting telescope, as Lord Rosse, Dr Robinson, Messrs Lassel, Na- 

 smyth, and Grubb, is decidedly of this opinion, — it seems strange that 

 the Government, which can hardly be expected to be very conversant 

 with the minute details of the practical accomplishment of such an 

 affair as this, should inform them that they are mistaken in their 

 idea of the practicability of what they have been engaged in for so 

 many years ; at least a committee might have been formed to com- 

 municate with these gentlemen, if the Government was really 

 favourably inclined, and to ascertain how the fancied difficulties could 

 be possibly met and overcome. 



That larger reflectors may be made now. than ever were before, 

 one has only to look to Lord Rosse's ; that they can be made far 

 cheaper I had abundant evidence recently, on being shewn one of 

 9 inches aperture, sold to George III. for £760, while another of 

 20 inches aperture, made the other day by Mr Nasmyth, and 

 which, so far as the increase of size goes, should have cost at least 

 five times as much, viz., in the proportion of the squares of the 

 apertures, not to say anything of superior excellence of quality, 

 cost him only £60 in work and material, exclusive of the value of his 

 own time in superintending. 



That the telescopes are also decidedly better, one has only to look 

 at the superior quality of the modern metal, so white and lustrous, 

 and free from pores, while the figures given to the surface by 

 machine in place of hand polishing have had their surpassing quality 

 undoubtedly tested by the performances of the instruments, — by the 

 resolution, for instance, of the nebula in Orion, although far from 

 favourably situated in these latitudes, and by the complete separation 

 of the second and third stars of y Andromeda, as well as by the ap- 

 pearance of small stars very close to large ones. 



The mountings of such telescopes have also improved, as witness 

 the simplification and solidity introduced into altitude and azimuth 

 stands by Lord Rosse and Mr Nasmyth, and the clock-moved equa- 

 torial mountings under revolving domes, of Dr Robinson, and Messrs 

 Lassel and Grubb. 



Doubtless there may be much room for improvement still, and the 

 variations and contrasts in the above mountings would seem to in- 

 dicate that the problem of devising the best form has not yet been 

 completely solved ; and I have no hesitation in confessing that not 

 one of the above stands is exactly conformable to my ideas of what it 

 should be, or rather what I should like to employ, if I had to make 

 the observations ; but nevertheless I should not attach any weight to 



