VOL. XV. (2) NOTES ON A DAILY WEATHER CHART 155 
pressure is highest in the centre, and gradually diminishes 
outwards. The air is calm and cool in the central portion, 
while, on the outskirts, the wind blows round the centre in 
the direction of the hands of a watch, not exactly parallel 
to the isobars, but spirally downwards (hence the high 
barometric readings) and outwards. 
Unlike a cyclone, which is commonly in rapid motion, 
an anti-cyclone is often stationary for many days together. 
The broad features of the weather in an anti-cyclone are 
blue sky, dry, cold air, hot sun and hazy horizon, with 
very little wind—in fact the very antithesis of everything 
which characterises a cyclone. 
Now, to return to our individual observer: he must 
have a barometer for reference and comparison, and, to be 
of any use, it should be one that gives a continuous record, 
z.€., a barograph, and, as its record is differential only, it 
should be set to, and checked by, a standard barometer, 
and the readings be corrected to sea level, as all synoptic 
readings are reduced to sea level before being used for 
forecasting. 
A week’s register shows the reading for any hour at 
a glance. Eight a.m. is the hour for which the readings 
from all the stations of the Meteorological Office are 
collected by wire at the central office, and are there plotted 
upon a chart for consideration and use. 
Now, if you take the daily chart, and, by means of 
a line drawn across it, translate it into a horizontal record, 
you will at once get a comparison with the readings of the 
barograph. 
Suppose, for instance, as well might be, that the system 
shown takes a week to travel over a certain point, the 
comparison would be complete, and would show the 
weather which would, in that time, pass over the single 
observer. 
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