Page:Small-boat sailing; an explanation of the management of small yachts, half-decked and open sailing-boats of various rigs; sailing on sea and on river; cruising, etc (IA smallboatsailing01knig).pdf/237

 of the rules that have been laid down by meteorologists:—

As the barometer is affected by the direction of the wind, the degree of moisture in the air and the force of the wind, the greatest rise or fall of the glass will occur when these act in conjunction.

The barometer is lowest for wind and rain together, as with a south-west gale, and also when a thaw succeeding a frost saturates the air with moisture.

The barometer is highest with cold and dry northeast winds, when the air is at its heaviest, and also during severe frost.

A sudden rise or fall of the barometer indicates a change in the weather that will not last long. But if the glass rises or falls steadily for several days, there will be a long continuance of whatever change of the weather is coming. As the sailors put it: 'Long foretold, long last; short warning, soon past.'

A barometer at about thirty inches, steady or rising, with temperature falling and moisture decreasing, indicates wind from the north-west round by north to north-east, or less wind. A falling barometer, with temperature rising and moisture increasing, indicates wind and rain, or snow, from the south-east round by south to the south-west.

It is important to remember that the wind usually veers with the sun—that is, in the Northern Hemisphere, from left to right. An easterly wind, for