338 



THE POPULAR SCIENCE MONTHLY. 



was made on the 6th of August last, in the Garden of the Tuileries, 

 Paris, on the occasion of the festival of the Union Franpaise de la 

 jeunnesse. An insolator, the reflector of which had an extreme diam- 

 eter of three and a half metres, or nearly twelve feet, was set up near 

 the steps of the Jeu de Paume. The steam generated in the boiler, 

 which was placed in the focus of the mirror, was applied to a small 



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vertical engine of thirty kilogrammetres power, and this was connected 

 with a Maroni press. Although the sun was not very hot, and the 

 radiation was interrupted by frequent clouds, the press was kept in 

 regular operation from one o'clock in the afternoon till half-past five, 

 printing on an average five hundred copies an hour of a journal spe- 

 cially prepared for the occasion, and called " Soleil- Journal " (Sun- Jour- 

 nal). This little experiment is not likely just yet to produce a revolu- 

 tion in the art of printing, but its success may enable us to judge, in 

 some degree, how useful the insolators may be made in latitudes where 



