Edwin. — Meteorology of Netv Zealand. 563 



the coast, because they do not all originate in the same place, 

 and also some travel into higher latitudes than others. There 

 are really three routes : (1.) Approaching from near Norfolk 

 Island towards but passing eastward of North Cape, and con- 

 tinuing thence toward south-east they pass to the northward 

 of East Cape. (2.) .From near Lord Howe Island travelling 

 south-eastward towards Cook Strait, or to some point on the 

 west coast of the South Island between Cape Farewell and 

 Hokitika (but also occasionally further southward), and, cross- 

 ing the South Island, continue towards south-east. (3.) Ap- 

 proach East Cape from about north or north-north-west, but 

 passing eastward of it, and when southward of it take a more 

 south-easterly direction. 



The lowest pressure of a cyclone travelling on about 

 route (1) usually passes North Cape about two days and a half 

 after passing Norfolk Island ; those of route (2) appear on the 

 west coast about four days after passing the meridian of Lord 

 Howe Island ; and those of route (3) have occupied about five 

 days from the western, part of the Fijian Islands. These 

 periods are sometimes apparently accelerated by the expansion 

 of the storm-area. Cyclones have sometimes two and occa- 

 sionally three areas of minimum pressure. This is shown by 

 there being only a partial restoration after the first decrease, 

 and this movement is followed by the wind soon changing 

 back to the direction it had at first, accompanied by another 

 and immediate decrease of pressure, these changes being 

 sometimes repeated a third time. The pressure curves regis- 

 tered under these conditions have a resemblance to those of 

 the westerly wave-pressures, but with this difference : that oi 

 two successive minima in a cyclone, the second may equal but 

 never exceeds the first, and the third is always the least. 

 These disturbances have always increased considerably in area 

 after leaving tropical latitudes, and have lost the extreme wind- 

 velocity they had when nearer to their point of origin ; but 

 some that arrive here have winds of nearly hurricane force, 

 and include the whole country within their area. 



The upper and intermediate clouds which precede and 

 accompany these low pressures are cirrus, cirro-stratus, and 

 alto-stratus, and when the latter cloud is conspicuous, remark- 

 ably well-defined halos with decided prismatic colouring are 

 seen. All these clouds come from the eastward, are generally 

 moving fast, and the ends of the cirrus are curled back toward 

 the direction they are coming from. The sunset colour with 

 these disturbances is always of a decided yellow, with occa- 

 sionally a tinge of orange towards the south. The yellow 

 sometimes deepens very quickly, and in such instances all 

 colour disappears almost immediately afterwards. 



