PROVISIONAL REPORTS, AND NOTICES. 433 
the barometric oscillations in those years, (to which, for the pre- 
sent, your Committee propose to limit their proceedings, til] it 
shall appear whether a further andmore complete comparison, in- 
cluding the thermometric changes, and especially the correspond- 
ence of the winds, seems likely to lead to any valuable conclu- 
sions,) tbe reduction, arrangement and projection of the several 
series of observations was confided to the able and zealous hands 
of W. R. Birt, Esq., who is now actively employed in the ope- 
ration, and who has enabled your Committee to lay before 
the meeting, as specimens of the mode of proceedings, the tabu- 
lation and projection of the observations made in the British 
Isles in the year 1836, which are accordingly submitted for in- 
spection. 
In the discussion of these observations it has been found ad- 
vantageous to divide the stations from which they have emanated 
into groups, according to geographical proximity, the chief of 
which are the group of the British Isles, that of the continent of 
Kurope and the North American, South African and Indian 
groups. Each of these groups is referred by applying the dif- 
ferences of longitude to the times of observation to a central 
station ; and the projected curves, in which the absciss# are the 
mean times at that station, and palmate the reduced barometric 
altitudes, exhibit at one view the correspondence or disagreement 
of the barometric movements for all the stations of the group. 
The numbers which serve for the projections are tabulated in 
the skeleton forms annexed, which appear well adapted for ge- 
neral adoption in such reductions, and of which, therefore, half 
a dozen blank copies are annexed as specimens for such members 
as may take an interest in the subject. 
The projection of these curves is the first step in the process 
of reduction contemplated ; and even in the very limited range 
afforded by the specimens now presented, affords ground for in- 
teresting remark. Thus, we see, that the march of the barcmeter 
in the only two Irish stations which have furnished observations 
(Markree and Limerick), while agreeing well with each other, 
differs most decidedly from its ‘corresponding march in all the 
English stations, which, on the other hand, offer a good corre- 
spondence inter se. A letter from Mr. Birt on this subject is 
annexed to the present report. 
It would be premature at present to enter fully into the de- 
tails of the further steps contemplated in these reductions, as 
they will be, of necessity, materially influenced by the aspect 
under which the subject shall present itself in its progress, and 
especially by the discussion of one or two of the most complete 
series, among which, thanks to American zeal and industry, the 
1840. 2F 
