IS 6 
FIFTH REPORT —1835. 
pated, more flattened as we advance northward, and lower in 
the scale. 
The ascending motion in the Leith curves is 9 hours 40 mi¬ 
nutes, and the descending motion 14 hours 20 minutes, which 
are to each other in the ratio of 2 : 3 nearly. The heat of the 
day in this case advances one third more rapidly than the cold 
of the night, but not so rapidly as at Plymouth, in the propor¬ 
tion of 4 :3. 
The form of the daily curves for the different months and the 
four seasons is seen in Places VII. and VIII. They are pro¬ 
jected from the mean results in Tables VI. and VII. 
In Plate VII. the curves evidently show three distinct varieties 
of temperature, as indicated by a general coincidence in the 
blue, red, yellow, and black lines, constituting the curves of 
spring, summer, autumn, and winter. These are more com¬ 
pletely reduced in PlateVIII.,in which we immediately distinguish 
the sharp, full curve of spring; the collapsing and less sharp¬ 
ened curve of autumn; the full, broad, rounded curve of sum¬ 
mer; and the low, flattened curve of winter. The autumnal 
curve evidently approaches more nearly to the curve of winter: 
its sides, instead of presenting a full appearance, rather tend to 
fall in, and assimilate with, the form of the winter curve; this 
is especially evident in the afternoon branch. The curve of 
spring, on the contrary, has its branches fuller and more rounded, 
and evidently approaches in general character the curve of sum¬ 
mer. These peculiarities in the general form of the respective 
curves are also observable in Plate VII. and are well marked in 
the curves of April and October; hence it seems more natural 
to class April with the summer months, and October with the 
winter. The respective differences and agreements in the curves 
of these months, which have been considered by many meteoro¬ 
logists as having a mean temperature equal to that of the whole 
year, are not unworthy of notice: they both approach the form 
and character of the annual curve, and to a certain extent re¬ 
semble each other; they differ, however, greatly in other re¬ 
spects. The general mean of October is above that of April, 
but the range of temperature is less. The mornings and even¬ 
ings of April are much colder than those of October, which are 
comparatively warm, and far above the mean temperature of the 
year. April, as observed at Leith, unites the low temperature 
of winter with the high range of summer; whilst October 
unites the high temperature of summer with the low range of 
winter. The great regularity of the curves of these months, as 
shown in Plate VII. as also the regularity of the mean curves 
observable in Plate IX. are very striking and remarkable. 
