Solar water heater. 19th century artwork of a parabolic solar water heater (upper right) powering a steam engine (centre) driving a printing press (centre left). This system was demonstrated on 6 August 1882, by a French engineer Abel Pifre. The demonstration took place at a meeting of the Union Francaise de la Jeunesse held at the Jardin des Tuileries in Paris. The parabolic mirror was 3.5 metres in diameter, with a cylindrical steam boiler at its focus. The press used here is a Marioni-type printing press. Although the sun lacked power and the sky was frequently overcast, the press operated for 4.5 hours in the afternoon, producing an average of five hundred copies per hour of Soleil-Journal (lower right), a journal published for the occasion.