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Reading the Barometer (Does so however near enough)

does so, however, near enough for ordinary practical purposes, provided that no sun, nor fire, nor lamp heat is allowed to act on the instrument partially.

The mercury in the cistern and tube being affected by cold or heat, makes it advisable to consider this when endeavoring to foretell coming weather by the length of the column.

Briefly, the barometer shows weight or pressure of the air; the thermometer, heat and cold, or temperature; and the wet thermometer, compared with a dry one, the degree of moisture or dampness.

It should always be remembered that the state of the air foretells coming weather rather than shows the weather that is present--an invaluable fact too often overlooked; that the longer the time between the signs and the change foretold by them, the longer such altered weather will last, and, on the contrary, the less the time between a A rapid rise of the barometer indicates unset. tled weather, a slow movement the contrary; as likewise a steady barometer, which, when continued, and with dryness, foretells very fine weather. The greatest depressions of the barometer are with gales from S.E., S., or S.W.; the greatest elevations, with wind from N.W., N., or N.E., or with calm.

Though the barometer generally falls with a southerly and rises with a northerly wind, the contrary sometimes occurs; in which cases, the southerly wind is usually dry with fine weather, or the northerly wind is violent and accompanied by rain, snow or hail; perhaps with lightning.

When the barometer sinks considerably, much wind, rain (perhaps with hail) or snow will follow; with or without lightning. The wind will be from the northward, if the thermometer is low, (for the season), from the southward if the thermometer is warning and a change, the shorter will be the con- | high. Occasionally a low glass is followed or attinuance of such foretold weather. To know the state of the air not only barometers and thermometers should be watched, but the appearance of the sky should be vigilantly noticed.

If the barometer has been about its ordinary height, say near 30 inches (at the sea level), and is steady, or rising while the thermometer falls, and dampness becomes less, northwesterly or northerly wind, or less wind, less rain or snow may be expected. On the contrary, if a fall takes place with a rising thermometer and increased dampness, wind and rain may be expected from the south-eastward, southward or south-westward. A fall with a low thermometer foretells snow. A rise during frost indicates snow.

Exceptions to these rules occur when a northeasterly wind with wet (rain, hail or snow) is impending, before which the barometer often rises (on account of the direction of the coming wind alone) and deceives persons, who from that sign only (the rising) expect fair weather.

When the barometer is rather below its ordinary height, say down to near 29½ inches (at the sea level), a rise foretells less wind, or a change in its direction toward the northward, or less wet; but when it has been very low, about 29 inches, the first rising usually precedes or indicates strong wind; at times heavy squalls from the northwestward, northward or northeastward, after which violence a gradually rising glass foretells improving weather, if the thermometer falls; but if the warmth continue, probably the wind will back (shift against the sun's course) and more southerly or southwesterly wind will follow, especially if the barometer's rise is sudden.

The most dangerous shifts of wind or the heaviest northerly gales happen soon after the baromeer first rises from a very low point, or if the wind veers gradually at some time afterwards.

Indications of approaching changes of weather and the direction and force of winds are shown less by the height of the barometer than by its falling or rising. Nevertheless, a height of more than thirty (30.0) inches (at the level of the sea) is indicative of fine weather and moderate winds, except from east to north occasionally or during frost, when northeast winds and snow are indicated.

The barometer is said to be falling when the mercury in the tube is sinking, at which time its upper surface is sometimes concave or hollow; or when the hand of the wheel barometer or Aneroid moves to the left. The barometer is rising when the mercurial column is lengthening, its upper surface being convex or rounded, or when the hand moves to the right. tended by lightning only, while a storm is beyond the horizon.

A sudden fall of the barometer with a westerly wind, is sometimes followed by a violent storm from N.W., or N., or N.E.

If a gale sets in from the E. or S.E., and the wind veers by the S., the barometer will continue falling until the wind is near a marked change, when a lull may occur, after which the gale will soon be renewed, perhaps suddenly and violently, and the veering of the wind towards the N.W., N., or N.E., will be indicated by a rising of the barometer with a fall of the thermometer.

Three causes (at least) appear to affect a barometer: 1. The direction of the wind; the northeast wind tending to raise it the most, the southwest to lower it the most, and wind from points of the compass between them proportionally as they are nearer one or the other extreme point.

N.E. and S.W. may, therefore, be called the wind's extreme bearings.

The range or difference of height shown, due to change of direction only, from one of these bearings to the other (supposing strength or force and moisture to remain the same), amounts in these latitudes to about an inch (as read off). 2. The amount taken by itself of vapor (moisture, wet, rain, or snow in the wind remaining the same), seems to cause a change amounting in an extreme case to about an inch. 3. The strength or force alone of wind, from any quarter (moisture and direction being unchanged), is preceded or foretold by a fall or rise, according as the strength will be greater or less, ranging in extreme cases to more than 2 inches.

Hence, supposing three causes to act together, in extreme cases, the height would vary from near 31 in. (30.9) to about 27 in. (27.0), which has happened, though rarely (and even in tropical latitudes).

In general the three causes act much less strongly, and are less in accord, so that ordinary varieties of weather occur much more frequently than extreme changes.

Another general rule requires attention, which is, that the wind usually appears to veer, shift, or go round with the sun (right-handed, or from left to right), and that when it does not do so, or backs, more wind or bad weather may be expected, instead of improvement. It is not by any means intended to discourage attention to what is usually called "weather wisdom." On the contrary, every prudent person will combine observation of the elements with such indications as he may obtain from instruments, and will find that the more accurately the