ON THE REDUCTION OF METEOROLOGICAL OBSERVATIONS. 97 
curve, exhibits the diurnal oscillations strongly but rather irregularly. Both 
minima, however, and both maxima are unequivocally made out. 
The Flushing and Gardiner curves both slope downwards nearly at an 
equal rate; the former very smoothly and gradually, the latter by four suc- 
cessive stages with levels between. In the former the descent is continued to 
the end of the term of 36 hours; in the latter a minimum is attained, and the 
last two hours of the series exhibit the commencement of a rise. The terms 
are too few for available comparison. f 
Dec. 1838.—Gardiner, Burlington, Flushing, Western Reserve College ; 
—Estero Real. 
(H.) The Gardiner curve exhibits a series of small and gentle undulations, 
superposed on a gentle and even convexity, culminating about 3 a.m., Dec. 22. 
In that for Burlington, with the same general aspect, the convexity is more 
considerable and its culmination occurs earlier, viz at 8 p.M., Dec. 21. Be- 
fore the end of the series, however, a point of contrary flexure occurs, and a 
minimum is attained at 2 p.m., Dec. 22, which is not the case at Gardiner. 
At Flushing the swell, the contrary flexure and the minimum are all more 
decided, giving a distinct culmination at 10 p.m., 21st, and point of greater 
depression at 3 p.M., 22nd. 
(H.) At Western Reserve College the whole series of thirty-six hours offers 
only one great concavity, the lowest point occurring at 4 a.m. of the 22nd. 
But we have no intermediate observations to connect this with the minima 
observed in the later hours of the Burlington and Flushing series, and the 
general aspect of the curves, as well as the much greater fluctuation, renders 
such connexion improbable. 
(H.) Estero Real is of course quite out of connexion with the above stations, 
but its curve is remarkable as exhibiting the finest specimen of the diurnal 
fluctuations of any we have yet passed in review. Its epochs and sums of 
excursions are as follow in mean time: 
m! M! m? M2 
4b 10% 158 2124, 
Sum of greater excursions.. (M* — m!) = 0°168. 
Sum of lesser excursions .. (M!— m*) = 0:037. 
Coneluding Remarks (H.).—Having now discussed in their order the ob- 
servations of each term, and stated the conclusions which have presented them~ 
selves in the course of their examination, it may be expected that I should 
express some opinion as to the utility of prosecuting a similar series of observa- 
tions more extensively, and on the objects chiefly to be aimed at in so doing. 
And here I must first. observe, that supposing any such continued series set on 
foot, it would be highly desirable, by previous communication ana concert, to 
secure a multitude of cooperators on chosen lines of connexion, so as to obtain, 
at least for those stations, more regularly continued series of terms than those 
which are comprised in our list, and to narrow in some degree the field of in- 
quiry by limiting it (as 1 have been compelled to do) to some distinct point of 
meteorology, such as the tracing of atmospheric waves and the determination 
of the coefficients of the diurnal periods. To the latter point the hourly system 
of observation alone is applicable, and monthly series (on the 21st of each 
month) of such observations from a vast number of stations in which abso- 
lutely nothing else was set down than the hourly march of the barometer 
for twenty-five consecutive hours (so as to begin and conclude the twenty-four 
hours with an observation), would in itself, if continued for a few years, leave 
1843, H 
