240 M. Arago on the Thermometrkal State 



XV. Co7ijectural causes of the increasing coldness of tJie Summers of 

 France and England, 

 This increasing coldness is evidently nol in the sun ; and the 

 constancy of the temperature of Palestine is a proof of it. Some 

 naturalists think it may be found in an unusual extension of the 

 ice-plains of the north pole ; in a general movement which, after 

 having carried them many degrees towards the south, has fixed 

 them to the coast of Greenland. 



It is certain that the eastern coast of Greenland was free of 

 ice when it was discovered towards the end of the tenth century, 

 by an Icelandic navigator ; that the Norwegians established them- 

 selves there; that, in 1120, the colony was numerous and flour- 

 ishing, and that it maintained a considerable commerce with 

 Norway and Iceland. It is also known that, in 1408, when 

 Andrew, the Bishop, the 17th in succession since the coloniza- 

 tion, went to take possession of his chair, he found the coast en- 

 tirely blocked up with the ice, and could not land. This state 

 of things continued, with some variations, up to the year 1813 

 or 1814. At that time there was an immense breaking up, and 

 the east coast of Greenland once more became free. The dete- 

 rioration, then, of the climates of Europe, it may be held, was 

 owing to the permanent existence of a vast plain of ice, which had 

 extended itself in latitude from Cape Farewell to the polar circle. 

 But this explication will be completely upset, by our consider- 

 ing that the document already adduced to prove that, in the 

 Vivarais and in Bourgogne^ the heat at a former period was 

 great ; and this about a century and a half posterior to the 

 formation of the icy plain on the coast of Greenland. It may 

 be added, that the entire breaking up which the ice underwent 

 in 1814, has produced in our climates, neither those conspicuous 

 changes which agricultural phenomena might reveal to every one, 

 nor even any of those slighter modifications, which the delicate 

 instruments of meteorologists might indicate to them. 



Let us now, then, consider if the cause of the variation in our 

 climates is not much nearer to us; and, if it does not depend 

 solely on those operations which the wants and caprices of an 

 unceasingly increasing population have produced on a thousand 

 points of territory. 



Ancient France, contrasted with France as it now is, presented 

 an incomparably greater extent of forests; mountains nearly 



