094 
cited among seamen in the study of the physical 
geography of the sea. It was a time of awakening 
to an opportunity of observation that had been too 
ice, le 
generally neglected before. But, in spite of their 
practical appearance, the Wind and current charts 
(or Track-charts, as they are commonly called) be- 
come unserviceable in the more frequented parts 
of the ocean, precisely where they are most needed, 
from the crowding together of observations. Along 
our coast and about the favorite longitudes for cross- 
ing the equator, the charts are unintelligible, except 
to the most painstaking examination, so completely 
are they covered over with a maze of signs and fig- 
ures and a tangle of lines. This difficulty was over- 
come in the Pilot charts, on which the winds were 
singled out and counted for place and time; the 
style of record being shown in fig. 2. The numbers 
in the corners give the total number of wind-observa- 
tions for each month in the given five-degree square; 
December, January, and February being in the north- 
east corner, and the others following in the order of 
hours on a clock-dial. The sixteen sectors of the 
circle include the number of times the wind was 
recorded for every month from the several compass- 
points to which they belong, the months being ar- 
ranged as in the sector below the square. The centre 
contains the number of calms for every month in the 
same order as the total winds. The absence of 
graphic representation of the winds, and the confu- 
sion arising from the number of figures required to 
show the whole year’s record on one sheet, were the 
chief disadvantages of these historic charts; but they 
were still vastly better than any thing of their time. 
Besides these, there were also prepared, about the 
same time, charts of the trade-winds and of the 
SCIENCE. 
vy eee te oe 
if 
& 49 
[Vor. IlL., No. 67. 
frequency of rain and storms. In the further devel- 
opment of the study, the treatment of the Atlantic 
winds will receive our chief attention. 
About 1855 a series of charts, based di- 
rectly on Maury’s Pilot charts, was pre- 
pared, under the direction of Admiral 
Fitzroy, for the London board of trade, 
on which the numerical form of record 
was replaced by graphic wind-roses for five- 
degree squares. These are known as the 
Board of trade wind-charts.! A little later 
Admiral Fitzroy published charts for the 
North Atlantic, showing winds, currents, 
temperatures, etc., for five-degree squares 
for February, May, August, and Novem- 
ber. These were based on logs obtained 
from the records of the Board of trade, as 
well as on Maury’s charts. In 1868 the 
hydrographic office of the British admi- 
ralty published its ‘Pilot charts for the 
Atlantic Ocean,’ giving Maury’s results, 
combined with those from all other attain- 
able sources, presenting the whole in sim- 
ple, graphic form, but without precise in- 
dication of the original observations on 
which the averages were based. ‘These are 
commonly quoted as giving the best general 
view yet published of the physical condi- 
tions of the Atlantic as a whole. Four 
large sheets show the winds for the four 
seasons, with the so-called ‘limits of the 
trades’ for every month; but insufficient attention 
. 
QS 
ne SE 
Sy 
» 
Hie. 2. 
1 Publications of the meteorological department of the Lon- 
don board of trade. Wind-charts of the North Atlantic and 
other oceans. 
Quart journ. meteorol. soc., London, 1877, iii. 190. 
oP f ‘a a ies tee le 
See the account of these charts by R. H. Scott, 
