Natural Philosophy— Astrcnoniy, ^201 
have thought it desirable, that the observation should be repeat- 
ed. This has been done lately by Captain Kater. He deter- 
mined the latitude of the station with an excellent repeating 
circle, and found it to be almost exactly the same as had been 
determined by that excellent astronomer Colonel Mudge, who 
has so ably conducted the survey. From this it seems to fol- 
low, that the cause of the apparent irregularity in tlie curva- 
ture of the terrestrial meridian, must be sought for elsewhere 
than in the astronomical observations. 
8. Sir William HersclieVs Researches respecting the Distance 
of the Fixed Stars .- — In a paper published in the Phil. Trans. 
1818, Part II, this celebrated astronomer endeavours, by 
computations founded on the known power of his telescopes, 
and the probable assumption of some certain average magnitude 
of the fixed stars, to arrive at definite conclusions on the great 
problem of the arrangement of celestial objects in space. 
Granting that, one with another, the faintest stars are tlie far- 
thest distant, their light then becomes, in some rough way, a 
measure of their distance, which may be compared by a series 
of equalisations between large and small stars, made with simi- 
lar telescopes, but of different apertures. He thus concludes, 
that a single star of the first magnitude would be just lost to 
the naked eye if removed to 12 times its distance, and to the 
most powerful telescope hitherto constructed, if to £300 times. 
Yet such -an instrument still continues to shew stars in the Mil- 
ky Way, at the utmost limits of their visibility. This wonder- 
ful sidereal stratum is therefore fathomless alike by our eves 
and by our telescopes. 
But though the light of single stars may no longer affect our 
organs, the united lustre of sidereal systems may reach us from 
a still greater profundity in space. IVhen the stars of clusters 
can yet be seen in telescopes, their distances may be estimated 
by the aperture which just resolves them, and in this v/av we 
have the distances of 47 clusters actually estimated in this pa- 
per. These, in turn, become connecting links v/ith such avibi- 
guous objects as our telescopes will not resolve. It is first pro- 
ved by many observations, that resolvable clusters seen wjtli in- 
ferior telescopes, actually put on similar appearances, and tlie 
similarity of nature once established, we may compare their dis- 
with those of the former kind, by the same principles' as 
