1823.] On HannibaPs Passage through the Alps. 139 



Temperatures. — The mean temperature for the year just 

 elapsed is 1° higher than that of the preceding one. The months 

 of April, May, August, September, and December, were consi- 

 derably warmer in 1821 than the corresponding ones of last year; 

 while the three first months, and June and July, are as much the 

 reverse. The means of October and November in both periods 

 are nearly alike. 



Rain. — The amount of rain exceeds that of last year upwards 

 of eight inches, and is the wettest we have had since 181ti. The 

 greatest monthly quantity fell in July, attended on five succes- 

 sive days with most tremendous thunder and lightning. 

 1 am, Sir, your most obedient servant, 



New Motion, Feb. 5, 1823. J. STOCKTON. 



Article VIII. 



On Hannibal's Passage through the Alps. 

 By Thomas M'Keever, MD. 



(To the Editor of the Annals of Philosophy.) 



SIR, 



Hardly any passage in the writings of Livy has been more 

 frequently the subject of comment than that in which Hannibal 

 is stated, during his celebrated and interesting march through 

 the Alps, to have effected the removal of a large cliff, which 

 impeded the progress of his army, by means of the joint agency 

 of fire and vinegar. 



As the particulars of this very remarkable event may have 

 escaped the recollection of some of your readers, it may not be 

 amiss to mention a few of the leading circumstances. Livy 

 informs us that Hannibal having, after a series of the most 

 frightful difficulties and dangers, reached the summit of the 

 Alps, rested there two days, in order to recruit his exhausted 

 troops : that he then commenced his descent, but had not pro- 

 ceeded far, when he came to a projecting cliff of great height, 

 which completely obstructed his further progress. Having in 

 vain searched for a more convenient route, he at length deter- 

 mined on levelling this formidable barrier, and for this purpose 

 ordered a number of large trees to be felled, and placed in a pile 

 at its base : they were then set on fire, and in a short time (the 

 wind proving favourable), so intense was the action of the heal, 

 that the solid rock became as red as the blazing fuel with wheh, 

 it was surrounded. Hannibal now thought of applying a quan- 

 tity of vinegar to its surface, which, it is asserted, had the effect 

 of softening its substance, and in this way a passage was spee- 



Neiv Series, vol. v. o 



