Aneroid Barometers. 61 



rain may be expected from the N.E., N., and N.W. 

 Exceptions to these rules occur when southerly winds with 

 rain and hail are impending, before which a barometer often 

 rises on account of the direction of the coming wind alone. 

 When the barometer is rather below its ordinary height, say 

 down to 29 Jin. at the sea level, a rise may foretell less wind, 

 or a change in its direction towards the south, or less wet ; 

 but when it has been very low, say about 29im, the first 

 rising usually indicates strong wind, at times heavy squalls, 

 from S.W.. S., or S.E. ; after which a gradually rising- 

 glass foretells improving weather, if the thermometer 

 falls ; but if warmth continue, the wind will probably 

 back, and more N. or N.W. wind will follow, especi- 

 ally if the rise of the barometer has been sudden, 

 and considerable, or if it is unsteady. The heaviest south- 

 erly gales happen soon after the barometer first rises from a 

 very low point. Indications of approaching change of 

 weather and direction and force of wind are shown much less 

 by the height of the barometer than by its falling or rising, 

 but a height of more than thirty inches at the sea-level is 

 indicative of fine weather and moderate winds, except from 

 S.E. occasionally, whence it may blow strongly with a high 

 barometer. A rapid rise of the barometer indicates un- 

 settled weather, a slow movement of some duration the con- 

 trary, as does likewise a steady barometer. A rapid and con- 

 siderable fall is a sign of stormy weather and rain ; alternate 

 rising and sinking, or oscillation, always indicates unsettled 

 disagreeable weather. The greatest depressions of the bar- 

 ometer are with gales from the N.E., N., or N.W. ; the 

 greatest elevations with wind from S.W., 8., or S.E., or with 

 calms. Though the barometer generally falls for a northerly 

 and rises for a southerly wind, the contrary sometimes occurs, 

 in which case the northerly wind is generally fine with dry 

 weather, and the southerly wind violent with rain and hail. 

 A barometer begins to rise considerably before the conclusion 

 of a gale, sometimes even at its commencement. It falls 

 lowest before high winds, but frequently sinks very much 

 before heavy rain. Instances of fine weather with a low 

 barometer occur, but they are always preludes to a duration 

 of wind or rain, if not both. Sometimes severe weather from 

 the northward of short duration may cause no great fall, be- 

 cause followed by a duration of wind from the south ward ; 

 and sometimes the barometer may fall with southerly winds 

 and fine weather, apparently against these rules, because a 



