Bertin commutator by Townson and Mercer, 34 Camomile Street, London EC. Bertin commutator by Townson and Mercer Science Teaching 1897-1918
Two Pohl commutators (see 2 stroke nos). Two Pohl commutators (see 2 stroke nos). Electricity and Magnetism 1872
Hand commutator, (for use with apparatus made by Walter Bailey, to show Arago's motion 1923-318) Hand commutator Electricity and Magnetism 1879
Commutator, Pohl type, by Philip Harris and Co. (1913) Limited Commutator, Pohl type Science Teaching 1920-1943
