ITALY. LETTER XV. 2QJ 



LETTER XV. 



Rome, dpril iS t 1772. 



SOON after I fent my laft, I made an ex- 

 curfion to Civka Vecchia and the alum- 

 works at Tolfa. I had the agreeable and 

 inftrucling company of Mr. Guettard, of Ba- 

 ron de Geer, and of Mr. Corea. However, 

 my curiofity has not been compleatly fatisfied, 

 fince the bad rainy and ftormy weather not only 

 made our obfervations very difficult, but likewife 

 hindered me from examining the country about 

 Tolfa. While I let you know what I had leifure 

 to obferve, I tell you the blanks, which you will 

 pleafe to fill up. 



As foon as we had patted the Porta fabrica at 

 Rome, which is near S. Peter's and the Vatican, 

 we obfervcd the continuation of the calcareous 

 hills on which the Vatican is fituated. Afterwards 

 the road was covered with brown fea fand, which 

 on both fides made fmall hills decked with brown- 

 yellow volcanic afhes. Near "the inn Montercne, 

 half way to Civita Vecchia^ I faw under the 



mould 



