August Toepler (7.09.1836-5.03.1912) was a German experimental physicist and a corresponding member of the Berlin Academy of Sciences (1879). He was born in Brühl.
In 1865 —69 he was professor at the Riga Polytechnic, in 1869 — 76 at the University of Graz (in 1875 he organised a Physical Institute at the university — one of the first in the world), and in 1876 — 1900 at the Dresden Polytechnic.
His research concerned optics, molecular physics, electricity and acoustics. He developed a number of research methods and instruments. He proposed (1867) the so-called schlieren method for studying optical inhomogeneities of a medium (the Toepler method), a variety of the shadow method. He invented (1865) the vacuum pump with a mercury piston (the Toepler pump). He built an induction machine (1865), a vibroscope for observing the vibrations of sounding bodies, a siren as a source of sound of a given frequency (the Toepler siren), an air damper for a galvanometer and others.