CATARACTS AND INUNDATIONS. 6? 



But in order to take matters regularly, I must first stop you 

 short of Tivoli about two or three miles, where the road is crossed 

 by a sulphureous stream, iu smell and taste very much resembling 

 that of Harrowgate, It flows with great rapidity between two stei-p 

 banks, that have not long since been made to carry it off. Here 

 my poor clog Turque (with whose face you are acquainted by Mr. 

 Tischbein's etching of it) had nearly fallen a sacrifice to my curi- 

 osity, or as you may perhaps call it my levity. Being desirous to 

 see how he would like bathing in a stream of such mauvaise odeur, 

 I threw a stoiie in, that he might dive for it. But he had no sooner 

 plunged, than the violence of the torrent carried him above a hun- 

 dred yards down, before we could overtake him, so as to give him 

 any assistance ; and even then, the banks were so exceedingly steep, 

 that it was not without difficuly we succeeded in our efforts to get 

 him out. 



Upon tracing this stream about a mile upwards, we found its 

 source in the little lake, from thence called Lago di So'fatara di 

 Tivoli, which is further remarkable for the phenomena of certain 

 little floating islands, some of which were fortunately driving about 

 in the wind at the time we arrived, and others at anchor in the bays 

 and harbours of this small lake. Our guide informed us they would 

 bear Christians, who very frequently get upon them and push 

 themselves about with a long pole for the amusement of strangers. 



There are remains of some ancient baths, which are known to 

 have been frequented by Augustus; and Galen mentions them as 

 being good for rheumatisms and cutaneous disorders, but at pre- 

 sent they are totally abandoned. 



It is extraordinary that these springs not only supply water for 

 bathing, but literally the materials also for building Laths. 



It appears that they formerly overflowed (as indeed they would 

 do at present, if not carried off by the channel abovementioned) a 

 large tract of land, and by their successive depositions of the cal. 

 careous particles that abound in them, have, in a series of ages, 

 formed immense quarries of an excellent stone for building, which 

 is called Travertine. 



This was in great use among the Romans, as appears from many 

 of the ruins which remain to this day, and particularly from the 

 Colosseum, or, great Amphitheatre of Vespasian, of which I gave 

 you an accouflt iu a former letter. I visited a quarry now working 



F 2 



