258 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
wind. Bearing this explanation in mind, the intelligent navigator 
will have no difficulty in understanding the wind diagram (Plate 
V.J, and in forming a correct opinion as to the degree of credit due 
to the fidelity with which the prevailing winds of the year are rep- 
resented on Plate VIIL 
As the compiler w^ades through log-book after log-book, and 
scores down in column after column, and upon line after line, 
mark after mark, he at last finds that, under the month and from 
the course upon which he is about to make an entry, he has al- 
ready made four marks or scores, thus (I I H). The one that he 
has now, to enter will make the fifth, and he " scores and talhes," 
and so on until all the abstracts relating to that part of the ocean 
upon which he is at work have been gone over, and his materials 
exhausted. These " fives and tallies" are exhibited on Plate Y. 
Now, with this explanation, it will be seen that in the district 
marked A (Plate V.) there have been examined the logs of vessels 
that, giving the direction of the wind for every eight hours, have 
altogether spent days enough to enable me to record the calms 
and the prevailing direction of the winds for eight hours, 2,144 
times : of these, 285 were for the month of August ; and of these 
285 observations for, August, the wind is reported as prevailing for 
as much as eight hours at a time : from N., 3 times ; from N.N.E., 
I; N.E., 2; E.N.E., 1 ; E., 0; E.S.E., 1 ; S.E., 4; S.S.E., 2; 
S., 24; S.S.W., 45; S.W., 93 ; W.S.W., 24; W., 47 ; W.N.W., 
17; N.W., 15; N.N.W., 1 ; Calms (the little O's), 5; total, 285 
for this month in this district. 
The number expressed in figures denotes the whole number of 
observations of calms and winds together that are recorded for 
each month and district. 
In C, the wind in May sets one third of the time from west. 
But in A, which is between the same parallels, the favorite quar- 
ter for the same month is from S. to S.W., the wind setting one 
third of the time from that quarter, and only 10 out of 221 times 
from the west ; or, on the average, it blows from the M^est only 
1^ day during the month of May. 
In B, notice the great " Sun Swing" of the winds in September, 
indicating that the change from summer to winter, in that region, 
is sudden and violent ; from winter to summer, gentle and gradual. 
In some districts of the ocean, more than a thousand observa- 
