Rear- Admiral FitzRoy on Meteorological Telegraphy. 403 



prevailed), either direct or deflected — deflected even through more 

 than one quadrant of a circle — by its advancing opponent, and 

 retaining for some considerable time its own previous characteristics. 



Thus we have for short times cold dry winds from the south-west, 

 instead of the usual warm and moist ones, or winds of this latter 

 kind from the north instead of cold ones. The circuitous tendency 

 of air in motion, and the numerous impediments to its horizontal 

 progress, such as land, ranges of mountains, hills, or even cliffs, 

 induce many a deviation from normal directions extremely puzzling 

 to the student of this subject; but so retentive is air of its tension 

 and temperature for a time, that, like currents in the ocean, each 

 may be traced by its characteristics as long as within our island web 

 of stations. When the polar current is driven back by a tropical 

 advancing from a southerly direction gradually, their action united 

 becomes south-easterly (from the south-eastward) ; and as the one 

 or other prevails, the wind blows more from one side of east or from 

 the other. 



So retentive of temperature are oceanic currents, that when H.M.S. 

 'Nile' was going from Halifax to Bermuda, in May 1861, Admiral 

 Milne found the temperature 70° at the bow while only 40° at the 

 stern, as he entered the Gulf-stream. 



Time is required to produce motion in the air horizontally ; time is 

 indispensable for its gradual cessation from movement. Statical 

 effects are noticed at observatories, or by careful observers any- 

 where, hours or days before dynamical consequences occur. 



The present daily forecasts or premonitions of weather are drawn 

 up on the following arrangement. Districts are thus assumed : — 



1. North Britain (including from the Moray Firth to the middle 

 of Northumberland), along the coast. 



2. Ireland, generally, around the coast. 



3. Central (Wales to the Solway), coastwise. 



4. East Coast (from Northumberland to the Thames). 



5. South England (from the Thames round to Wales), by the 

 coast. 



As our space is very limited, and as some words are used in dif- 

 ferent senses by different persons, extreme care is taken in selecting 

 those for such brief, general, and yet svfficiently definite sentences as 

 will suit the purpose. 



Such words as are on published scales of force or nature of wind 

 and weather are generally understood, and therefore used in pre- 

 ference to others. 



In saying on any day what the probable character of the weather 

 will be tomorrow, or the day after, at the foot of a table showing 

 its observed nature that very morning, a limited degree of informa- 

 tion is offered for about two days in advance, which is as far as may 

 be yet trusted generally, on an average, though at times a longer 

 premonition might be given with sufficient accuracy to be of occa- 

 sional use. 



Minute or special details, such as showers at particular places, or 

 merely local squalls, are avoided; but the general or average charac- 



2E2 



