Infiuence of the Polar Ice on other Climates. 199 



Barnmetr'ical Olservnt'tovs. 

 The barometer on the 26th of January and 1st of April at- 

 tained the extraordinary height of 73 centimetres (27 inches) ; 

 and on the 1st of November, at 52 minutes past eleven at night, 

 it exceeded that by one degree and 6-lOths of a hne, which is 

 a millemetre more than the height to wiiich the mercury rose oh 

 the 23d of February 1815. 



XXXIII. On the Influence ivhkh the Increase or Diminution 



of the Polar Ice has on the Climates of other Latitudes. 



To Mr. Tilloch. 



Sir, — If the following observations appear of sufficient im- 

 portance to merit a place in your journal, their insertion will much 

 oblige your sincere well-wisher, 



March 9, 1813. Z. A. 



One perpetually finds given as a reason of the great cold in the 

 high latitudes of the southern hemisphere, the great accumula- 

 tion of ice round the south pole. That popular writers should 

 transfer an idea derived from what we experience when ice is 

 hrovght into a warm neighl)ourhood, or what we experience 

 when ice, formed in the neighbourhood or in the place itself, be- 

 gins, from the action of new and extraneous causes, to warm and 

 melt — that they should have transferred this idea to the general 

 and total effects of ice formed in any place, is not at all sur- 

 prising; — !)Ut that the same notion should have been adopted by 

 so many scientific persons, is indeed a lamentable proof, among a 

 thousand others, how little the world is improved in the art of 

 strict reaso.iing. 



The formation of ice in anv place tends to warm the neigh- 

 bourhood, not to cool it. If the ice, without melting, accumu- 

 lates year after year, there is obviously a perpetual yearly accu- 

 mulation or accession to the world of free coloric; namely, of 

 all that set free by the conversion of the water from a fluid to a 

 solid state. And consequently, whatever partial cold may be 

 produced, ihe geiier at effect is an increase of warmth. Suppose 

 the water of a lake in any country to become ice — What is the 

 cause of this change ? Not the presence of the water surely ; 

 but either the abstraction or the locking i/p of caloric in the neigh- 

 bourhood, in consequence of certain grand processes of nature of 

 which we know vothing, and which we do not imagine to depend 

 on the existence of a lake in that place. This abstraction of ca- 

 loric reduces the temperature about the lake below the freezing 

 point; and then, by the tendency of contiguous bodies towards 

 equal temperatures, (of the laws of which tendency we know 



N 4 something. 



