SOUTHERLY BURSTERS. 37 



the west as the cool breeze advances, and down the rain comes in 

 torrents, and in a few hours all, wind and rain, is over. Thunder 

 may or may not accompany the rain, which almost always precedes 

 (at least in Bio Grande) pamperos. I have seen pamperos as 

 strong after rain, when there was no thunder accompanying, as 

 when there was. Our thunder, too, is generally, in the summer 

 and rarely in winter. I must add that Rio Grande being further 

 north than the Plate, we do not get the pamperos with the full 

 force experienced in the Plate region. With us they are a steady 

 continuous blow for three days, varying little in force till the third 

 day, when they are felt to be grudually declining. They always 

 blow from the same quarter, the south-west, and are cold and dry." 



The most interesting fact evidenced in this description of the 

 pampero is that it always follows rain. This would seem to imply 

 that the evaporation arising from the plains is one of the immediate 

 causes of its existence. If this is the case it lends support to the 

 theory, hereinbefore submitted, that the vapour arising after rain 

 from the vast heated areas of the Australian interior is at least 

 one of the agencies from which the burster has its origin. The 

 difference between the two sets of circumstances is that, in South 

 America, the cause and effect act on the same region, and there- 

 fore one follows the other with no appreciable interval, while in 

 Australia the seat of the effect is removed by something like one 

 thousand miles from that of the cause, and consequently the con- 

 nection is more difficult to trace. 



Winter northers of Texas are a somewhat similar experience. 

 The following is a short extract : " The northers prevail from 

 November to March, and commence with thermometer at 80 or 

 85. A calm ensues on the coast ; black clouds roll up from the 

 north ; the wind is heard several minutes before it is felt ; the 

 thermometers begin to fall ; the cold northers burst upon the 

 people bringing the thermometers down to 28 and sometimes even 

 to 25, men and cattle being killed from the severe cold." This is 

 the only description I have come across of similar changes in the 

 northern hemisphere. * 



1 Physical Geography of the Sea by Maury, pp. 93-94. 



