BY G. R. SMALLEY, ESQ. 349 



for the most ordinary purposes ; as available for regulating a 

 town clock as for conducting a navy to the Indies ; as effective 

 for mapping down the intricacies of a petty barony, as for 

 adjusting the boundaries of transatlantic empires." 



" When once its place has been thoroughly ascertained and 

 carefully recorded, the brazen circle with which that useful work 

 was done may moulder, the marble pillar totter on its base, 

 and the astronomer himself survive only in the gratitude of 

 posterity. But the record remains, and transfuses all its own 

 exactness into every determination which takes it for a ground- 

 work, giving to inferior instruments, nay, even to temporary 

 contrivances and to the observations of a few weeks or days, all 

 the precision attained originally at the cost of so much time, 

 labour, and expense." 



Such are the opinions so elegantly expressed by this great 

 philosopher, in the introduction to the catalogue of 8377 fixed 

 stars, published by the British Association, for the advancement 

 of science. Yet, out of the countless number which optical 

 improvements bring within our sphere of observation, 1500 only 

 appear to be accurately recorded : of these, the catalogue just 

 referred to, furnishes the most reliable portion. Perhaps, the 

 number of those which have been determined with very great pre- 

 cision, does not exceed 2000, whilst of the fundamental stars or 

 those selected for the nautical almanac there are 141. Hitherto, 

 the fixed stars of the Southern Hemisphere do not appear to have 

 received their due share of attention, and it is only now, that 

 there seems to be some prospect of those observatories which 

 possess first-class meridian circles, co-operating in forming a 

 complete catalogue, of all stars up to the ninth magnitude, after 

 the example of Argelander, in the Northern Hemisphere. 



Among the improvements which have been made in astrono- 

 mical instruments, none perhaps deserves more attention than 

 the method now almost universally adopted for observing bodies 

 on the meridian. Previous to 1850, it was usual to employ two 

 instruments for the purpose. A transit instrument, by means of 

 which the time of a star's passing the meridian, and hence the 

 right ascension was obtained ; and a mural circle which furnished 

 the stars altitude when on the meridian. These two ele- 



