1) Measuring instrument 
instrument for measuring purity or richness of milk
• (n.) An instrument for estimating the amount of cream contained in milk by ascertaining its relative opacity.
Lac'to·scope noun [ Latin lac , lactis + scope .] An instrument for estimating the amount of cream contained in milk by ascertaining its relative opacity. 
Type: Term Pronunciation: lak′tō-skōp Synonyms: galactoscope
A lactoscope (lactometer, galactometer) is an instrument for measuring the amount of cream in milk (that is the quality of milk). Several instruments of this sort have been invented. One simple example consists of a glass tube one foot long, graduated into 100 parts. New milk is filled into it and allowed to stand until the cream has fully separate...