16 E. Loomis—Reduction of Barometric Observations. 
yaar and the observations are arranged in the same manner as 
table I. Table VII shows the principal barometric maxima 
on Pike's Peak during a period of three years. 
he numbers in each of these tables were divided into four 
equal groups, and the average of the numbers in each group 
was taken. The results are given in the first five columns of 
table III, and the numbers in the other columns were computed 
in the same manner as has been explained for Mt. Washington. 
We see that for os Nweglad minima, the differences between 
they are quite large; but when the computations are made by 
Ferrel’s tables the average difference between theory and 
observation is almost exactly the same in both cases, with the 
exception of the algebraic signs. These soanlis accord with 
those for Mt. Washington i in indicating that the pressure coefh- 
cient in the Laplace formula is too small. The value of the 
pressure coefficient which best represents the Pike's Peak 
observations i is 60357, and that of the temperature coefficient is 
or barometric minima, the average difference between 
the observed reduction and that tt by Ferrel’s formula 
is less than half of that found for the Mt. Washington observa- 
tions, a result which may be ascribed, at ‘least in part, to the 
feebler winds which prevail on Pike's Peak. 
or barometric maxima, the differences for Pike’s Peak com- 
puted by Ferrel’s formula are greater than for Mt. Washington, 
the date of barometric maximum at the upper station; an 
small changes of pressure at one of the stations which are not 
felt (or in a less degree) at the other station. now of no 
observations which indicate what effect may be ascribed ‘to the 
first of these causes in the present a but probably the effect 
is sma e effect due to the second cause is often quite 
large. The barometer at Denver (after a maximum) generally 
begins to fall from eight to sixteen hours sooner than on Pike's 
eak, and it sometimes falls a quarter of an inch or more 
before the descent begins at Pike’s Peak. Thus Dec. 13.8, 1873, 
fter an uncommonly high pressure, the barometer at Denver 
fell ‘28 inch before the barometer at Pike's Peak began to fall. 
Again Jan. 14.1, 1874, the barometer at Searee was at a maxi- 
mum, from which time it fell for four days uninterruptedly 
with the exception of two slight reactions, one amounting to 
‘Ol inch and the other to-04 inch. Tbe barometer at Pike’s _ 
Peak did not begin to fall until after Jan. 16.1, when the 
