The Tortelli thermoleometer is used to measure the thermo-sulfuric degree of oil to reveal adulterations. By thermosulphuric degree we mean the thermal rise that 20 ml of oil undergo with 5 ml of sulfuric acid. The thermal excursion is constant and characteristic for each type of oil. It is due to the breaking of the double bonds operated by sulfuric acid.

In the wooden box there are two double-walled glass beakers in whose cavity the vacuum has been made, three pipettes and a glass bottle.