of the Terrestrial Globe. 5835 



that which produces the death of laurels ; and thus it could not 

 much surpass that of 55°, The habitual vegetation of the lau- 

 rel and myrtle gives us 57° at the least ; and the occasional 

 death of laurels has just given us a number somewhat above 55°. 

 These two conclusions perfectly agree with the supposition of a 

 constant mean temperature ; for, to repeat, this temperature is 

 now 60°. 



Varro places the vintage between the 21st of September and 

 the 23d of October. The mean, at present, in the neighbour- 

 hood of Rome, is the 2d of October. The dates then, do not 

 oppose the conclusion we have drawn from the culture of the 

 myrtle and the laurel. 



Is an additional proof required that, in ancient times, the 

 plains of Romagna were not so cold as certain authors have al- 

 leged ? They may be supplied from two interesting notices of 

 Virgil, and Pliny the naturalist. In ascending the Apennines to 

 a certain height above the sea, we find a great number of beau- 

 tiful trees, which cannot now-a-days bear the high temperature 

 of the lower regions, and amongst which I shall be satisfied with 

 naming the pitch pine (Pinus picea) and the common fir. 

 Well, then, in ancient times, these same trees did not descend 

 to the plains. Both Virgil and Pliny expressly state that the 

 high mountains are the sole localities in which they are to be 

 found. 



But we are anxious to acknowledge that, in this discussion, 

 the data which it was necessary to employ, to a certain extent, 

 have lacked that peculiar character, which recently allowed us, 

 in reference to Palestine, to confine its ancient temperature be- 

 tween two numbers almost equal to one another. Nor need we 

 much regret it. For, so far as it regards Rome, had we succeed- 

 ed in establishing a difference of climate to the extent of 4° or 

 5°, we should not, from want of data, which would with certain- 

 ty have informed us of the ancient state of the country compared 

 with the present, have been able to discover the cause of the 

 change. 



XIII. Change of the Climate of Tuscany, 



In the letter to ApoUinarius, already referred to (p. 234.), the 

 younger Pliny declares, that the climate of his residence in Tus- 

 cany was not favourable either to myrtles or olives. And yet 



