Densimeter
Otherwise called aerometer and alcoholmeter (due to its gradual scale), the densimeter consists in a glass cylinder, in the lower part ballasted by mercury and in the upper part provided of a thin graduated glass torch. The specific weight is obtained plunging the densimeter into an hydroalcoholic liquid. But by the temperature increasing also the liquid volume rises and consequently the specific weight reduces; in addition to the alcoholmeter gradation some suitable correcting schedules have been created in order to give the exact alcohol percentage according to different temperature degrees.
