Friedrich HeerenFriedrich Heeren (11 August 1803 – 2 May 1885) was a German chemist.
He received his doctorate in Göttingen, and from 1831 was an instructor of technological-chemical subjects at the Polytechnic School in Hannover (''Höheren Gewerbeschule''). Here he taught classes in physics, mineralogy and chemistry.
With technologist Karl Karmarsch (1803-1879), he published a technical dictionary (''Technisches Wörterbuch''). Also, with Karmarsch, he developed a process for the preparation of gun cotton. In 1881 he introduced an apparatus for the testing of milk (lactometer, patent# 241655). Provided by Wikipedia