532 THE VAL DI CHIANA. 
suspension of the works of improvement in the Maremma, but 
they were resumed after the revolution of 1859. 
I have spoken with some detail of the improvements in the 
Tuscan Maremma, because of their great relative importance, 
and because their history is well known; but like operations 
have been executed in the territory of Pisa and upon the coast 
of the duchy of Lucca. In the latter case they were confined 
principally to prevention of the intermixing of fresh water 
with that of the sea. In 1741 sluices or lock-gates were con- 
structed for this purpose, and the following year the fevers, 
which had been destructive to the coast population for a long 
time previous, disappeared altogether. In 1768 and 1769, the 
works having fallen to decay, the fevers returned in a very 
malignant form, but the rebuilding of the gates again restored 
the healthfulness of the shore. Similar facts recurred in 1784 
and 1785, and again from 1804 to 1821. This long and repeated 
experience has at last impressed upon the people the necessity 
of vigilant attention to the sluices, which are now kept in con- 
stant repair. The health of the coast is uninterrupted, and 
Viareggio, the capital town of the district, is now much fre- 
quented for its sea-baths and its general salubrity, at a season 
when formerly it was justly shunned as the abode of disease 
and death.* 
Improvements in the Val di Chiana. 
For twenty miles or more after the remotest headwaters of 
the Arno have united to form a considerable stream, this river 
flows south-eastwards to the vicinity of Arezzo. It here sweeps 
round to the north-west, and follows that course to near its junc- 
tion 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 — 
* GroraInI, Sur les causes de V Insalubrité de (air dans le voisinage des ma- 
rais, etc., ue dV Académie des Sciences d Paris, le 12 Juillet, 1825. Reprinted 
in SALVAGNOLI, Rapporto, etc., appendice, p. 5, ef seqq. 
