514 THE VAL DI CHIAISTA. 



is now mucli frequented for its sea-baths and its general salubrity, 

 at a season wben formerly it was justly shunned as the abode of 

 disease and death.* 



Im/provements in the Vol di Chia/)ia. 



For twenty miles or more after the remotest headwaters of the 

 Arno have united to form a considerable stream, this river flows 

 southeastwards to the vicinity of Arezzo. It here sweeps round 

 to the northwest, and follows that course to near its junction 

 with the Sieve, a few miles above Florence, from which point 

 its general direction is westward to the sea. From the bend at 

 Arezzo, a depression called the Val di Chiana runs southeastwards 

 until it strikes into the valley of the Pagha, a tributary of the 

 Tiber, and thus connects the basin of the latter river with that 

 of the Arno. In the Middle Ages, and down to the eighteenth 

 century, the Val di Chiana was often overflowed and devastated 

 by the torrents which poured down from the highlands, trans- 

 porting great quantities of shme with their currents, stagnating 

 upon its surface, and gradually converting it into a marshy and 

 unhealthy district, which was at last very greatly reduced in pop- 

 ulation and productiveness. It had, in fact, become so desolate 

 that even the swallow had deserted it.f 



* GiORGiNi, Sur les causes de V Insaluhrite de I'air dans le voisinage des ma- 

 rais, etc. , lue d I' Academic des Sciences a Paris, le 12 Juillet, 1825. Reprinted 

 in Salvagnoli, Bapporto, etc., appendice, p. 5, et seq. 



f This curious fact is thus stated in the preface to Fossombroni {Memorie 

 sopra la Val di OMana, edition of 1835, p. xiii.), from which also I borrow 

 most of the data hereafter given with respect to that valley : " It is perhaps 

 not universally known, that the swallows, which come from the north [south] 

 to spend the summer in our climate, do not frequent marshy districts with a 

 malarious atmosphere. A proof of the restoration of salubrity in the Val di 

 Chiana is furnished by these aerial visitors, which had never before been seen 

 in those low grounds, but which have appeared within a few years at Fojano 

 and other points similarly situated." 



Is the air of swamps destructive to the swallows, or is their absence in such 

 localities merely due to the want of human habitations, near which this half- 

 domestic bird loves to breed, perhaps because the house-fly and other insects 

 which follow man are found only in the vicinity of his dwellings ? 



In almost all European countries the swallow is protected, by popular opin- 

 ion or superstition, from the persecution to which almost all other birds are 

 subject. It is possible that this respect for the swallow is founded upon 



