Cll 
General Results of the Makeestoun Obseevations. 
214. Sums of the Pressures luith tuhich the Wind bleiu from each of the 16 Principal Points of the Com- 
pass. — Following tlie same procedure as in No. 213, we obtain the following sums of pressui'e from four years' 
observations, of 24 a-day, the sums being of the maximum pressures observed within 10™ at the hours of obser- 
vation. (See No. 198.) 
N. NNE. NE. ENE. E. ESE. SE. SSE. S. SSW. SW. WSW. W. WNW. NW. NNW. 
lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. 
711 757 722 442 217 84 163 362 749 1945 3411 1262 990 693 689 654 
The sums of pressures obey nearly the same laws as the frequency with which the wind blew ; the greatest sum 
of pressures occurred a few degrees south of SW. ; the sum then diminishes to W., varies little from '\A'NW. to 
N. being, on the whole, less at NNW. than for the adjacent points ; it becomes a secondary maximum about 
NE. by N., a principal minimum at ESE. (See curve a in the figure, p. ci.) 
215. Mean Pressure luith which the Wind bleiu from each of the 16 Principal Points of the Compass. — 'Di- 
viding the sums of pressures for each of these points (No. 214) by the number of observations for which the 
wind was observed blowing at 0-1 lb., or upwards (No. 213), we obtain the following mean pressures with whicli 
the wind blew from each of the 16 points : — 
N. NNE. NE. ENE. E. ESE. SE. SSE. S. SSW. SW. WSW. W. WNW. NW. NNW. 
lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. lb. 
0-91 0-57 0-43 0-51 0-50 0-47 0-50 0'63 0-69 0-73 0-81 0-65 0-82 0-95 0-74 0-75 
The wind blew with the greatest force from WNW. and N., and with the least force from NE. and ESE., 
but the mean force was nearly constant between NE. and SE. The mean force witli which the wind blew be- 
tween NNE. and SSE. = 0-52 lb., between NNW. and SSW. = 078 lb., or in the ratio of 2 to 3. ^yhen 
the projection of the previous values upon the directional radii are connected, a very symmetrical figiire is 
formed, having three minima at intervals of about 80°, namely, at NE., NW by N., and WSW. (See curve 
c in the figure, p. ci.) 
Motions of Different Cuerents of Air. 
216. Difference of the Directions of Motion of the Upper and Loiver Currents of Air. — The mode in whicli 
the directions of motion of the clouds were observed is described in the introductions to the previous volumes 
in the section, " State of the Sky.'' The pi'ocess by which the results for the differences of motion of the dif- 
ferent currents were obtained by the combination of simviltaneous observations, ■will be found stated in the 
volume for 1844, p. 440. The detailed results for each of the four years 1843-6 are given in separate tables in 
the present and in the previous volumes. The total number of comparisons of the currents of scud, cirro-stratus, 
and cirrus, with the surface-current, and of the cirro-stratoiis and cirrous-cui*rents with the scud-current, was in 
1843, 865 ; the numbers of results (each of from five to two comparisons) were in 1844, 995 ; in 1845, 964 ; 
and in 1846, 541. In the disciission for 1843 only one or two simultaneous observations were termed a com- 
parison ; from five to two simultaneous observations were termed a result for the three follo\ving years (see 1844, 
p. 440) ; but as the values of the final results for each year were not considered gTeatly different, the numbers 
of comparisons of 1843, diminished by a tenth, have received the weight of the results in the following years, 
and the numbers of results for 1846 were increased by a half in the combinations given below. The weights 
of the four years 1843, 1844, 1845, and 1846, were taken on the whole, therefore, as 779 : 995 : 964 : Sll. 
217. The scud-current inchides the cumulus ; the cirro-stratous cxirrent includes also the cloud termed in the 
Makerstouu Observations the cirro-cumulo-stratus : this cloud, so frequently seen, has received no name in 
Mr How.v^rd's classification ; it belongs to the region of the cirro-strati, and is composed of great numbers of 
clouds like small cirro-strati, arranged with a cirro-cumulous disposition. After this name liad been applied to 
this cloud for some time, I discovered that Mr ITowARn had given it already to the Nimbus. The cirrous 
current includes the cirro-cumulus. The order of i-cckoning being from north, by the cast, south, and west, 
one current is considered positive of another when it proceeds from a point more southerly in the eastern semi- 
circle and more northerly in the western semi-circle. 
218. When we consider the resiilts for each quadrant, we find they present diHorcnces, both in tlie values 
and signs of the mean differences of the directions of motion ; in three of the quadrants, however, namely E to 
S., S to W., and W to N., the signs are the same ; in every case the mean upper currents proceed from points 
positive of the currents below them. In the qiuulrant S to W. by far the greatest number of results have 
been obtained, and tliey are by far the most regular and distinct. Thus, in 774 results, each obtained from several 
comparisons oC llu' current of scud with the snrfaco-wind. 664 shewed the scud-current to proceed from a point 
