the Caldana
The geothermal system responsible for Acqui's well-known thermal springs actually extends over much of the Visone area, giving rise here too to several warm sulphurous springs; and, as with the Acqui springs, knowledge and use of these sources date back to very ancient times.
There were once many thermal springs in the area. Today only the Caldanaremains, an ancient spring known as far back as Roman times, located in the southern historic centre of the village, near the presbytery of the parish church and just beyond the “Opera Regina Pacis” theatre building.
Until the first half of the 20th century it had two open-air basins fed by two different springs: one hot and one cold.
During the Second World War the partition dividing the two springs was demolished, so that the two spring waters began to mix into a single flow. The basin was then covered with a walkable slab, still in place today.
“In the municipality of Visone, District of Rivalta d'Acqui, nine and a quarter metres east of the Parish House, there is a sulphurous spring called the Caldana […], which rises at several points within a basin 6.16 metres long and 4.11 wide, enclosed by a wall.
Where it flows, this water forms a filamentous, yellowish deposit of sulphurous nature; it has a faint hepatic odour and a slightly salty taste. Its temperature was found by Doctor Baldissone at the beginning of December 1820 to be +16 degrees, with the atmosphere at +3 degrees. Among the various springs enclosed in the basin, some are warmer than others, so that, if the former were separated, water of a higher temperature could be obtained.
The Caldana of Visone has not yet been analysed. The inhabitants use it to treat goitre. The mud at the bottom of the basin is applied with benefit to aching limbs.”
[from: B. Bertini, Idrologia minerale, ossia storia di tutte le sorgenti
d'acque minerali note sinora negli Stati di S.M. il Re di Sardegna,
Turin, 1822, pp. 136-137]