Continuing work on the. use of river currents to generate, hydroelectricity without the use of dams, a new prototype floating unit was constructed which generated 1 kw of electricity when anchored in a current, of 1,1 m/s. The electricity was generated in 110 V and 60 Hz with manual control. Protecting the machine against floating debris (principally floating islands of vegetatation) was identifed as the major problem in the development of this technology. The upper and lower Amazon (Rivers Solimões and Amazo-nas) were shown to have current., depth and potential sufficient for the use of river-mills of this type in all the places investigated.