272 YEAR-BOOK OF FACTS. 



racter ; but its central part passed just to the west of Ireland's south- 

 west coast, and thence north-eastward. 



Of both these gales the barometer and thermometer, besides other 

 things, gave ample warning ; and telegraphic notice might have been 

 given in sufficient time from the southern ports to those of the 

 eastern and northern coasts of our islands. 



At it is the north-west half of the cyclone (from north-east to 

 south-west, true) which is influenced chiefly by the cold, dry, heavy, 

 and positively electrified polar atmospheric current, and the south- 

 west half that shows effects of equatorial streams of air — warm, 

 moist, light, and negatively electrified ; — places over which one part 

 of a cyclone passes are affected differently from others which are 

 traversed by another part of the very same meteor, or atmospheric 

 eddy, the eddy itself being caused by the meeting of very extensive 

 bodies of air, moving in nearly, but not exactly opposite directions, 

 one of which gradually overpowers, or combines with the other, after 

 the rotation. 



On the polar half of the cyclone, continually supplied from that 

 side, the visible effect is a drying up and clearing of the air, with a 

 rising barometer and falling thermometer ; while on the equatorial 

 side, overpowering quantities of warm moist air, rushiug from com- 

 paratively inexhaustible tropical supplies, push towards the north- 

 east as long as their impetus lasts (however originated), and are suc- 

 cessively chilled, dried, and intermingled with the always resisting, 

 though at first recoiling, polar current. After such struggles these 

 two currents unite in a varying intermediate state and direction, one 

 or other prevailing gradually. 



Very plain and practical conclusions are deducible from these con- 

 siderations : — 



One, and the most important, is, that in a gale which seems likely 

 to be near the central part of a storm, that should be (of course) 

 avoided by a ship which has sea room ; a seaman, facing the wind, 

 knows that the centre is on his right hand in the northern hemi- 

 sphere, on his left in the southern ; he therefore is informed how 

 to steer. 



Another valuable result is that telegraphic communication can 

 give notice of a Storm's approach, to places then some hundred miles 

 distant, and not otherwise forewarned. 



ANTKillTY 01 " TIIK LAW OK BTOBKB." 



Mil. HKKLIS has communicated to the British Association a 

 notice of an old work on the Origin and Nature of Wind, by K. 



Uohun, of New College, Oxon, published at Oxford in I871j and 

 which contains a statement of various points in the Latw of Storms, 

 Buoh as their vortical motion, calm oentre, change of current 

 action upon the barometer, twenty-seven years earlier than the 

 earliest account. bi1 Bed, which is that of Captain Langford, 



in the Philosophical Trcmtactiotu for 1698. 



