258 EVOLUTION OF SULPHURETTED HYDROGEN. 
annually in the neighboring country with all their peculiar 
horrors: the population, though small, presented feeble infants 
and diseased men, old age being unknown there. All attempts 
to avoid the scourge, by living on the hills, or in the interior, 
and frequenting the plains when the business of cultivation 
essentially required it, were vain ; they fell victims to the 
extensive influence, and such being the effects upon the in- 
habitants of the country, much more rapidly did a stranger 
suffer from the deleterious atmosphere ; one single night in 
the months of August and September causing inevitable death 
to the incautious traveller who should stay so long in this in- 
fested country. 
"Such was the state of things till 1741. Previous to that 
time Gemignano Rondelli, Eustachio Manfredi, and Bernar- 
dino Zendrini had successively insisted upon the necessity of 
excluding the sea from these marshes ; and in 1740-41 a 
sluice with folding doors, competent to give emission to the 
waters of the marsh, but prevent the sea from entering, was 
constructed at the mouth of the Burlamacca. The most com- 
plete and unexpected success immediately followed upon, and 
has continued with this work. The year after its completion 
there were no appearances of the terrible maladies which pre- 
viously appeared every year. The inhabitants soon recover- 
ed health, and the land being very fertile, the population 
rapidly increased, and is increasing at this moment. Viareg- 
gio has become a considerable town ; and so completely has 
all suspicion of its insalubrity disappeared, that the first fami- 
lies of the city of Lucca have for years built their summer 
seats there. Notwithstanding the success of the precautions 
taken at this part of the coast, the neighboring parts were long 
left a prey to the destroying influence of the mixed marsh- 
waters ; and the inhabitants around the basins at Motrone and 
Perotto were not considered until the year 1804. In the 
years 1809, 1810, 1811, similar means were taken, with the 
best effects, to the inhabitants of Montignoso and the vicinity ; 
and in 1812 a sluice was constructed on the Cinquale, which 
perfected the arrangements in this part, and made a large por- 
