—_—_— 
May 30, 1884.] 
same area in Toynbee’s monograph has for March 
only 6,823 wind-observations. One of the five-degree 
squares (No. 676, latitude 0° to 5°, longitude 20° to 
25°) into which the ocean is divided on our charts 
has 10,329 hours of record : this is practically equiva- 
lent to a continuous hourly record in this square for 
nearly fourteen Marches. If the other months main- 
tain the same number of North Atlantic observations, 
liters 1 
the year’s average would be based on about 2,500,000 
hours of record. On the other hand, many coast 
squares, and most of those off Newfoundland and 
Labrador, have insufficient observations. The wind- 
observations in this vast quantity of material come - 
from the Maury records and from more recent logs 
in about equal number, but the data on the side of 
the squares rest on the recent logs alone. 
Chief attention is given to classifying the wind in 
direction and force, as this is the factor of greatest 
use to the practical seaman. The percentage of the 
number of observation-hours during which the wind 
is recorded as having blown from every two points of 
the compass is shown by the fractional radius drawn 
inward from the appropriate part of the circle within 
the square. The average force for every wind-direc- 
tion, in units of the U.S. navy (= Beaufort) wind- 
scale, is measured by the number of divisions, out- 
side the circle. (fig. 1), connected by a cross-line. 
The percentage of calms and variable winds is shown 
on the radial percentage scale by a ring and a cross 
at the centre of the circle. North-west and north- 
east gales (G) are shown in percentages on the top of 
the square; south-west and south-east, at the bottom. 
Moderate squalls (MS) and heavy squalls (HS) are 
placed on the lower half of the left and right sides of 
the square, rain (R) and fog (F) being above them. 
All these are given in percentages of their total 
hours,! and consequently, when taken together, give 
to the navigator a very close measure of the kind of 
weather he may expect for any part of the North 
Atlantic south of 50° latitude. The figures in the 
1 The legend on the charts states that these side data rest on 
a smaller number of hours than is recorded for the general wind- 
observations. 
SCIENCE. 
655 
corners of the squares record the average stand and 
the average daily variation of the barometer (B), air- 
thermometer (A), wet-bulb thermometer (W B), and 
sea-thermometer (S W), thus completing the list of 
the more important and practically useful climatic 
elements. The most serious omission is the number 
of observations on which these side data depend. 
The mechanical execution of the work is excellent. 
The charts, twenty-seven by thirty-four inches, are 
clearly and sharply engraved. The figures are, per- 
haps, rather fine, being smaller than in the accom- 
panying cut, which does not fairly represent the 
clearness of the original, but they are not so fine as 
some in Toynbee’s work; and some of the lines are 
too delicate for rapid reading, but they are perfectly 
distinct on a closer examination. Some ease of 
counting might be gained by emphasizing the fifty- 
per-cent divisions, as here marked. . In comparing 
the graphic method of these new charts with the 
numerical and verbal form of record in the volume 
for the North Pacific,! issued by the hydrographic 
office a few years ago, it is difficult to make a choice, 
except as a matter of preference. The results shown 
are about the same in both. On the Pacific charts, 
from which a five-degree square is given in fig. 2, 
the number of observations, and average force of 
the wind for every two points, are given in the outer 
circle: the percentage that these observations make, 
of the total of winds, calms, and variables, is in the 
inner circle. The other data explain themselves. 
In the centre there is a verbal description of the 
characteristic local weather, for which there is no 
space in the Atlantic charts. But the frequency of 
gales from the four quadrants is not shown; and 
(No. 142), 
No. of 4ours of 
Hire. 2. 
in making a comparison of winds from square to 
square, or even within a single square, the numbers 
have first to be read, and then compared; which is 
certainly more difficult than when the wind percent- 
ages and strengths are expressed in lines, whose 
1 Meteorological charts of the North Pacific Ocean from the 
equator to latitude 45° north, and from the American coast to the 
180th meridian. Washington, 1878. (Prepared under the direc- 
tion of Lieut. T. A. Lyons.) 
