ON THE REDUCTION OF METEOROLOGICAL OBSERVATIONS. "7 






: Angle with meridian Distance in | Time of tra- 
cenit of line joining them. | statute miles.| versing it. 
Edinburgh to London ... aie 330 728 
London to Brussels ...... 75 100 6 °7 
Brussels to Geneva ...... 16 330 #39 
Geneva to Parma......... 62 220 10 *1 

These stations divide themselves into two classes; those whose directions 
are little inclined (the lst and 3rd pairs) to the meridian, and those (the 
2nd and 4th) whose directions are much inclined. The mean of the former 
gives 660™ in 15" 7™, or 42™-0 per hour in a mean direction, 17° 30! inclined 
to the meridian; that of the latter, 320™ in 168 8™, or 19™-0 per hour in a 
mean direction, 68° 30! inclined. These data, by the resolution of a plane 
triangle whose sides are 42:0 and 19:0 respectively, and the included angle 
= 68° 30’ — 17° 30' = 51° 0! give 10° for the inclination of the front of the 
wave to the meridian, or a direction of progress from 10° N. of W. to 10° S. 
of E., and an actual velocity of 18°62 miles per hour. 
From this, as well as from the moderate range of the observations at Mar- 
kree, it would appear that in fact neither of the points which we have termed 
the first and second culminations were observed at that station, and that the 
maximum actually observed was in the nature of a protuberance on the slope 
of the wave analogous perhaps to what we termed the third culmination in 
the Edinburgh observations. 
The winds of this term offer many points of interest. At Edinburgh we have 
mention of “strong winds” rising into “ violence” at 17 hours and 21 hours 
from S.and §.W. In London, high wind in the morning of the 21st, from N. 
passing into N.N.E., the mercury being rising, whereas at the time of the 
violent winds at Edinburgh (at a later hour) it was falling. And it is further 
noticeable that in the London series a complete reversal of the direction of the 
wind took place before the end of the term, passing from N. by the E. to S., 
thence ranging to S.W., and finally settling in the S. with abated force. At 
Halifax also a similar reversal of direction from N.E. round by E., S.E., S.W. 
to W., and then settling back to S.W., was observed, as the barometer rose, 
culminated and fell, the strongest indication being from the W. at 20 hours, 
Dec. 21. At Beaumaris, the change of direction was from N.W. (very light) 
by W. (moderate) to W.S.W. (strong), the maximum of strength being about 
midnight of the 21st. The Oxford series begins with a high but subsiding 
wind from N., with rising barometer, passing round by E. to S.W., and dying 
into a calm with a falling one. At Brussels the changes were as in London, 
beginning from N., passing round by E. as far as N.N.W., then settling back 
through W. and S.W., and at the same time dying away from the time of the 
culmination so as to obliterate the gradations of its shift. At Geneva the 
_ series began with violent wind from S. and S.W., settling into calm as the 
mercury rose. At Kremsmiinster, gentle from N.W. and N. during the first 
half of the series, calm during the last. On the whole, I am disposed to re- 
gard the winds recorded as the sequel of a more violent gale antecedent to 
the series observed. 
The discussion of this highly interesting term has detained us long. Nevers 
theless it is impossible to conclude it without remarking on the elucidation 
which EVEN A SINGLE Frencu sTATION would have afforded, of the discon- 
nexion of Cadiz from the others; and I cannot but add some expression of 
regret, that in all our accumulated observations we have none from France, 
the whole of whose vast territory thus interposed (with Spain and Portugal) 
