This thermometer, ending in a spherical bulb, is divided into fifty degrees, one of the many thermometric scales adopted by the Accademia del Cimento. The upper part of the stem carries inscriptions in white enamel. The degree marks on the stem are also of enamel: the black dots indicate single degrees, the white ones ten degrees. The thermometric liquid is acquarzente. Invented by Grand Duke Ferdinand II de' Medici, fifty-degree thermometers were generally used to measure the variations in heat and cold of the air, both outdoors and indoors. The academicians made extensive use of the instrument, chiefly for meteorological observations: the advantage of these thermometers was that their readings were comparable with one another, even though they were not the most sensitive.