Notice sur des Expériences exécutées avec la Machine Dynamo-électrique
et avec la Lampe á arc Voltaïque de M. Jürgensen

 Experiments with the Jürgensen dynamo-electric Machine and arc lamp. In 1882 the Jürgensen dynamo-electric machine and lamps were in operation at the Cowper Street Schools of the Finsbury Technical College and at Messrs. Johnson and Phillips’ Works, Charlton; it has been subjected to numerous tests by Profs. Ayrton and Perry, whose re- ports we are enabled to publish. Preliminary Report on the Jürgensen dynamo-electric Machine at Messrs. Johnson and Phillips’ Works, Charlton. By Professors W. E. Ayrton and John Perry, M. E. London, 1st August, 1882. This machine is what is known as a „series dy- namo“, that is, the field magnets are in series with the revolving armature. The two specialities of the machine are — 1st, an internal fixed electro-magnet, which together with the external fixed electro-magnet produces the magnetic field in which the armature revolves. 2nd, the special shape given to the external magnets causing them to follow the lines of magnetic force, and therefore theore-