Revolution Counter, with five discs
1858
Revolution Counter German electric induction type
Sectioned Revolution Counter MkIV a.(mechanical)
Revolution Counter MkIV by Smith
German clock type revolution counter and indicator
Sectioned Revolution Counter WD
German Revolution Counter by Morell No. 81184
Sectioned Revolution Counter MkV
Jaeger clock type revolution counter
German Revolution Counter by Dr. TL.Horn Leipzig
Revolution Counter
Combined Revolution counter and stop watch in case
Small Hand revolution Counter
Casagrande liquid-limit apparatus
German Revolution Counter
TEL' German revolution counter
'TEL' German Revolution Counter
Improved form of mechanical counter, late 19th century.
late 19th century
Mechanical counting device, c 1900.
circa 1900
Aircraft engine revolution counter.
Revolution counter, inscribed with numbers
1862
revolution counter used on a waterwheel
Casagrande liquid-limit apparatus
1967
revolution counter
1960