5. Johann Efraim
Frolland's regulator,
around 1810-1816,
see ill. 3,4
(Phot. Stanisław
Stefan Mieleszkiewicz)
101
Frolland's regulator,
around 1810-1816,
see ill. 3,4
(Phot. Stanisław
Stefan Mieleszkiewicz)
101