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JJelliummodel377●JJJacobi,MoritzHermannvon(Photo)(Sep.,,Potsdam,Germany–Mar.,,St.Petersburg,Russia)JacobiwasaGermanphysicistandengineerwhoworkedmainlyinRussiaonpracticalap-plicationsofelectricity.Hisresearchonelectromagnetsandtheirapplicationsinelectro-generatorsandelectro-motorswasofgreatpracticalimportance[i].Inhedesignedoneofthefirstelectro-motorsandinheconstructeda-ftboatpropelledbyanelectricmotorwithalargenumberofbatterycells.Itcarriedpassen-gersontheNevaRiver,St.Petersburg,ataspeedofthreemilesperhour.In,Jacobideveloped�galvanoplas-tics(alsocalledelectrotyping)[ii]–themethodformak-ingduplicateplatesforrelief,letterpress,orprinting.Healsocontributedtothedevelopmentofwiretelegraphy.Refs.:[i]JacobiMH()Mémoiresurl’applicationdel’électro-magnetismeaumouvementdesmachines.EggersetCie,SanktPeters-burg;[ii]JacobiMH()DieGalvanoplastik.EggersetCie,SanktPe-tersburgEKJacobicurrentstrength(intensity)—Obsoletedefini-tionofthestrengthofcurrent.�Jacobihassug