234 DISCUSSION OF THE DESICCATION QUESTION. 



old records are mentioned, from which Arago seems authorized to deduce the 

 result that the summers are not so hot and the winters not so cold in Tus- 

 cany as they were when the observations in question were made (1655- 

 1670).* The shortness of the series, and the fact that only maxima and 

 minima can be used for comparison, render the conclusions drawn from them 

 of little or no value. 



Arago proceeds in bis inquiry by quoting a few lines from the Misopogon 

 of the Emj^eror Julian, describing his life at Paris about the year 358, 

 and speaking of the mildness of the winters, and of the fact that figs and 

 grapes could be grown there without difficidty. No comments are appended 

 to this statement ; but in the next chapter, headed " Changes of Climate in 

 certain Parts of France," the author remarks that the documents he is about 

 to submit to the reader seem to prove that in certain regions of France 

 the summers are not so hot as they were formerly. A detailed statement, 

 drawn from ancient records, follows, indicating quite clearly that the grape 

 no longer matures as early as it did 300 yeai's ago, and that since that time 

 the northern limit of profitable or possible viticulture has moved southward. 

 On the strength of this evidence Arago considers himself justified in making 

 the following statement : " Here is enough, as it appears to me, to convince 

 the most incredulous that with the lapse of time the summers have lost, both 

 in France and England, a notable part of their heat." Nothing had been 

 said up to this point in Arago's work in regard to changes of climate in Eng- 

 land, although that country is included in the above-cited remark. Farther 

 on in the volume evidence relating to that country is introduced of a charac- 

 ter similar to that previously given in regard to France. It is stated, on the 

 authority of an article in the Proceedings of the Royal Institution, that there 

 is abundant evidence that the vine was once successfully cultivated in Eng- 

 land, and that it is gradually becoming more difficidt to raise even apples 

 profitably. 



Arago, after having proved, as he thinks, that the summers in France and 

 England have become cooler, proceeds to discuss the reasons of this change, 



* The observations in question were taken by Fatlier Ranieri, at the Convent degli Angeli in Florence, with 

 an instrument whieli was one of a lot constrneted under the sujiervision of the Academy del Ciniento and distrib- 

 uted by theui to volunteer observers at different poiuts. Of course these tlierinometers had no fixed scale, and 

 the observations made with thcin could not have been used at all had not a box contaiuing instruments of the same 

 make been accidentally discovered in 1828. These were compared with our present standard thennometers by 

 Libri, and the results of Ranieri's observations publi.Jied as reduced to our scale. This paper forms tlie basis of 

 Arago's conclusions, which see n to be more positive than those of libri himself. 



