Uima vaya Mountains. 205 
not correct, we were anxious to divide the observations on both sides of the 
zenith as much as might be, though that could not always be effected. ‘Those 
observers who fancy they can determine latitudes with portable refleciing 
instruments to the exactness of a second or less, will be surprised to see 
ihe discrepancies which our lists present, even at the Belville station, where 
we were not vexed by tempests and mists. It will be seen, that some of the 
results vary 10, 12, 15 and more seconds occasionally on both sides of the 
mean; but when it is considered that in an instrument of six inches radius, 
iwenty seconds is a very small space, being only the i455 part of an inch, 
difficult fer the maker to divide, and perhaps more so, for the observer to 
read, and that the telescopes are of small power, it seems hardly warranta- 
ble to suppose that any number of reflections can reduce the uncertainty to 
less than five or six seconds, nay perhaps double that quantity. Indeed 
if small instruments are capable of this accuracy, they do more than 
considering their size, can proportionably be expected from them, when 
we see that observations for latitude made with the most perfect zenith 
sectors of five and eight feet radius, and used by such skilful observers 
as Colonels Munger and Lamsron, vary in some instances as much as eight 
seconds from each other, and by referring to the notes of those distin- 
guished astronomers Messrs. DeLtampre and Mecuain, who in the great 
survey of the French meridian used the repeating circle, it will be seen 
that the results of observations for latitudes taken from the same, and by 
different stars and on different nights, did occasionally differ from each 
other, twenty and even thirty seconds: though in the use of the re- 
peating circle, these casual discrepancies are no doubt rendered of little 
er mo consequence, in the mean given by the very great number of 
