o.- Mountains in New York. 
which sustains the column of mercury, arising from fluctuations, 
that are independent of temperature, and for which no provision 
is made in most formulas, and the discrepancy in the results as 
given by different formulas, all claiming to be equally correct. 
Errors from these sources when they occur so as to affect the 
result differently, may neutralize each other, but when they ope- 
rate the same way, may produce a very considerable deviation 
from the truth. In the observations of Mr. Emmons, the barome- 
ter at Whiteface was compared with the barometer at Burlington 
and Albany, and if I rightly understand him, the mean of the two 
was taken, the difference being about 100 feet less at the former 
than at the latter. .The time of making the observations was 6, 
A. M. of the same day, Sept. 21. In the record which he gives 
of the state of the barometer at the two latter places at noon of 
the same day, the fact is made known that while the baromet- 
ric column fe// at the one place it rose at the other, causing @ 
difference equivalent to upwards of 100 feet of elevation. Com- 
puting the elevation of the place of observation at Burlington at 
6, A. M. above tide from the observation at Albany at the same 
time, and it gives 500 feet, nearly. Taking the observations 
made at the same places at 12, M. of the same day, and the re- 
sult is 390 feet, nearly. Which of these is correct, or whether 
either is only known from the fact that the elevation in question 
has been ascertained by the common mode of levelling to be 372 
feet, nearly, giving a maximum deviation from the truth in tw 
observations only, of 128 feet, nearly. In the case of the obset- 
vation on the summit of Whiteface, there exist no data by which 
the relative conditions of the atmospheric column as compared 
with the same column at Burlington and Albany can be ascel- 
tained.. 
Whiteface is about 35 miles west of Burlington, the nearest of 
the points mentioned, but far enough, it is believed, for considet 
able difference to exist. But one observation is recorded as hav- 
ing been made on its summit and that not under the most favor 
able circumstances, since it is stated that the “ wind was strong 
from the northeast and cloudy.” In the case of Mt. Marcy, the 
comparison was made with the barometer at Albany. In cousé- 
quence of the greater distance of the places of observation, a much 
greater error might result than in the case of the observations a 
Whiteface and Burlington. That the greater discrepancy 
tween the barometric and trigonometric elevations of Mt. Mar 
