Transnrtions. 15 



28-40 in., at mid-day to 28-00 in., and about G p.m. it reached 

 the extremely low point of 27-61 in., after wliich it began slowly 

 to rise till, at 9 p.m., tlie reading was 27-70 in. The depression 

 moved from west to east — as such depressions for the most part 

 do — and had a very extensive area, embracing all the west of 

 Europe. Readings below 28-5 inches were observed in all parts 

 of the kingdom, but the nortii of Ireland and England and the 

 south of Scotland appear to have been the centre of the depres- 

 sion. At Belfast the reading at 1.30 p.m. was 27-38 in.; at 

 Dumfries about 6 p.m., 27-60 in.; and at Leith a little later, 

 27-65 in. This circumstance — of the South of Scotland being in 

 tiie centj-e of tlie depression — is probably the explanation of the 

 fact that, though tlie barometer fell nearly as low as in the great 

 storm of January, 188-i, and in some places even lower, tlie force 

 of tiie wind was not nearly so great as in that destructive storm. 

 Ill these cyclones, as they are called, it is well known tliat the 

 wind, instead of blowing in a rectilinear direction, wliirls round 

 the depressions, and is most violent at some distance from the 

 centre, or area of lowest pressure, which is often compai-atively 

 calm. The south of Scotland and nortli of England appears to 

 have been the centre in this instance, but farther soutii, on the 

 coast of Wales and in the English Channel, tliere was a violent 

 gale, which caused much destruction to shipping. For an 

 example of an opposite condition of barometrical pressure, or 

 anti-cyclone, a term used to describe an extensive area of hi<rh 

 pressure with .slight gradients, the month of September may be 

 referred to, when for twelve successive days, from the 13tJi to 

 the 25th, with one exception, the barometer stood above 30 in., 

 culminating in 30-58 in. on the 15th. During tliat time there 

 were ten successive days on which no rain fell, from the 15th to 

 the 25th. A still better example was furnished by tlie latter 

 part of June and the beginning of July. From the 26tli June 

 to the lOtli July, a period of fourteen days, the barometer ranged 

 from 29-98 in. to 30-43 in., and during that time the winds were 

 very light, and only one-hundredth of an inch of rain fell. It is 

 not without reason, therefore, that a continuous high state of the 

 barometer is commonly associated with settled weather, for the 

 period mentioned was by far the finest and warmest part of the 

 summer. The theory of meteorologists regarding tiiese cyclones 

 and anti-cyclones is that the atmosphere wliich envelopes the 

 earth resembles an ocean, which, like the sea, is more or less 



