The Barometer.

Golden Bay Argus, Volume 4, Issue 35, 25 January 1895, Page 2

The Barometer.

What the Rising or the Falling of the Meroury Indicates. Certain people have attempted to establish rules by which the coming state of the weather may be predicted from the height of 1 the meroury in the barometer ; and we accordingly find the words “rain,” “ changeable," “ fair,” “frosty," (to., engraved on the) scale attached to common domestic Baro*' meters, as if, when the mercury stands at the height marked by these words, the weather is always subject to the vicissitudes expressed by them. These marks are, however, entitled) to no attention, and it is only surprising to) find their use continued in the present times, 1 when knowledge is so widely diffused. Two barometers, one near the level of the Hudson River and the other on the top of Trinity steeple, will differ by half inch, the latter being always have an inoh lower than the' former. If the words, therefore, engraved, upon the plates are to be relied on, similar 1 changes of weather could never happen at these two situations. But what is even more absurd, such a eeale would inform us that the weather at the foot of a high building must always be different from the weather at the top of it. Changes of weather are indicated, not by the actual height of the meroury, but by its change of height. One of the most general, though not absolutely invariable, rules is that where the mercury is very low, and ■herefore the atmosphere very light, high ■vinds and storms may be expeoted. The following rules may generally :e relied upon, at least to a certain exlent : 1. Generally the rising of the meroury in* fioates the approach of fair weather; tha Ailing of it Bhows the approach of foul voather. 2. In sultry weather the fall of the mercury indicates coming thunder; in winter the rise Df the mercury indicates frost; in frost iti fall indicates thaw, and its rise indicatei mow. 3. Whatever ohange of weather suddenly follows a change in the barometer may bt sxpeoted to last but a short time. Thus, if lair weather follows immediately the rise ol the mercury, there will be very little of it j and in the same way, if foul weather followl the fall of the meroury, it will last but t short time. 4. If fair weather continues for several days, during which the mercury continually Falls, a long continuance of foul weather will probably ensue; and again, if foul weathei sontiuuesfor several days, while the meroury continually ripes, a long succession of fail weather will probably succeed. 5. A fluctuating and unsettled state of th( mercurial oolumu indicates ohangeabli weather. The domestic barometer would become t muon more useful instrument if, instead ol ihe words usually engraved on the plate, a short list of the best established rules, such is the above, accompanied it, which might be jither engraved on the plate or printed on a ;ard. It would be right, however, to express ;he rules only with that degree of probability which observation ol past phenomena has justified. Tmre is no rule respecting these fleets which will hold good. In explanation i t it be known that when the mercury falls fins action shows only that the atmosphere oas become lighter. Now, inasumoh as moist lir is lighter than dry air, it is assumed that when the atmosphere changes from a heavier to a lighter condition it also becomes more moist; and so it generally does, but this is not i ways the oase.