414 
DE. T. E. EOBINSON ON THE SEDUCTION OE ANEMOGEAMS. 
Summer Day. 
Sum W=3519 m, 23 ; Sum S=5454*50 ; Ann. Translation= 6491 ; D=32° 50'. 
Summer Night. 
Sum W=2831 m, 43 ; Sum S=5081 - 65 ; Ann. Translation =5 81 7 ; D=29° 8'. 
Both components are more than twice as great in winter as in summer ; the day com- 
ponents are greater than the night ones, except the winter S. 
The sums of all are Sum W=21514”-40 ; Sum S=33303”; Ann. Trans. = 39648” ; 
D = 32° 5T. 
On examining the records of the components, I find that 630 hours were missed by 
various accidents, so that the total number of hours is 60714; and the above sums, 
X 7 y -u60714 h , will give for the mean hourly values W=2 m, 4805; S=3 m, 8398 ; 
V=4 m, 5713 ; 0=32° 54' 44". The value of V shows that the wind in the first quadrant 
is nearly half the total amount. 
The monthly means of the components are given in the following Table (p. 415). 
On examining this, Table we observe, First, that all the values both of W and S 
are positive ; in other words, that in a considerable number of observations the aerial 
currents from west and south have at this station a decided predominance over all the 
others. Secondly , that, as was anticipated, however discordant the results of individual 
hours or days may be, yet the means of from 196 to 217 present a notable agreement, 
and the differences which they exhibit are evidently subject to law. If we look down 
the vertical columns (which give approximate values for each hour of the middle day 
of each month) we find in each a decided maximum and minimum, and another, or 
even more than one of each, less in amount. The hours of these phases vary with the 
months ; that of the principal maximum occurs in the winter months from noon to 
3 p.m. for W ; in the summer from 9 a.m. to noon ; for S it varies less, being a little 
before noon. 
The principal minimum occurs in the evening, from 6 p.m. to 10 p.m., both for W 
and S. The extreme diurnal ranges are greatest in March, being for W 2”T4, for 
S 2 m, 40 ; they are least in November, being 0*74 and 0-79. 
It deserves notice that during the winter months the horary values of W for the four 
afternoon hours exceed those for the four that precede, the sum of the differences being 
9 m, 95. In the summer months the reverse is the case, but the — differences are only 7 m- 02. 
Does this arise from the great extent of land to the east of Ireland as contrasted with 
the ocean to its west, and the greater evaporation from the latter in summer 1 
If we examine the horizontal columns (which show the monthly variations) the 
dominion of Law is still more manifest. W has a maximum in January, a minimum 
in February; the greatest maximum is in March, the least minimum in April: these 
abrupt changes are remarkable ; but it is possible that the great value of W in March 
is abnormal, and may not occur in subsequent years. It then increases with a slight 
