June 15, 1S8S. 



SCIENTIFIC NEWS. 



555 



hours, while the temperature remains nearly constant. The 

 furnaces can be worked with the dust of coke, anthracite 

 or any non-caking coal, or with larger coal of very poor 



They serve also for heating, fumigating, and disinfecting 

 chambers, for drying fruits and many other articles of 

 food. In France they are also used extensively for heat 



Fig. I. — Longitudinal Vertical Section. 



quality, yielding as much as 30 to 40 per cent, of ash. 



As regards the purposes for which such furnaces are 



suitable, we may mention that they are used for drying 



Fig. 2. — Transverse Vertical Section. ^'15^'4i 



ing churches, schools, hospitals,"and other buildings. In 

 this country, however,' there is a decided and reasonable 

 preference for heating buildings by a'circulation of hot 



-Longitudinal Vertical Section. 



Fig. 4. — Transverse Vertical Section. 



and evaporating of all kinds. They are much used in 1 water, but for the thousand and one purposes for which 

 France and Belgium for heating malting floors, also for drying and heating are required in manufacturing pro- 

 heating pans and other apparatus in sugar refineries. I cesses M. Ferret's system is deserving of close attention. 



