20 On the supposed Change 



Dr. Holy oke mentions the description of the severe 

 winter A. U. G. 536, in the second Punic war,Avhen the 

 siege of a town in Spain, near the present Barcelona, was 

 obstructed by snow which lay for thirty days to; the depth 

 of four feet....&^ Memoirs of Am. Academy., vol. ii. 70. 



From these representations, it is concluded that Italy 

 has now a much more temperate climate than at and be- 

 fore the Christian era. Let us examine this point. 



Dr. Holyoke gives us the mean of the greatest cold at 

 Rome, deduced from several years' observations, with- 

 in the last half century ; which is 33° 46, a little above 

 freezing point. The greatest cold is stated at 31.°. If 

 we admit this statement to be correct,^ then Dr. Williams 

 has stated the extreme of cold in Rome almost nine de- 

 grees too high ; of course we must deduct nine degrees 

 from his seventeen degrees of alteration, in eighteen 

 centuries, which is a very material difference. 



This we must do, and more. For Brydone in the win- 

 ter of 1769 — 70,. found the greatest cold at Rome in Jan^ 

 uary to be 27°, a degree capable of covering large rivers 

 with a thin coat of ice. That winter was perhaps cold- 

 er than usual ;. but by no means of the severest kind. — 

 At Naples, says Brydone, we had rainy weather ; at 

 Rome, it was clear and frosty. That Vv^inter then would 

 at Rome produce all the phenomena of ice, frost, and 

 snov/, to answer the description of the Latin writers of 

 the Augustan age. 



If the mean temperature of the winter's cold at Rome 

 is now about 33°, it is not more than eight degrees mild- 

 er weather than in Nev/ England ; for Dr. Holyoke found-, 

 by seven years' observations, that the mean winter tem- 

 perature at Salem, in Massachusetts, is 25° 74. 



I know not the position of the thermometer by which 

 the observations at Rome v/ere made. But I would re- 

 m,ark that, if those observations were made in the city, 

 they do not represent the general temperature of Italy. 

 I found by numerous observations in New-York, that 

 ice as thick as glass in our windows, w^as uniformly 

 made at a mile's distance from the city, when an accu;- 

 rate thermometer in the coldest positions in the city stood 

 at 40°. Such is the difterence between the real tempe- 



