482 PROCEEDINGS OF THE AMERICAN ACADEMY 



XXII. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON THE BEHAVIOR OF SOUND AND DECAYED 

 WOOD AT HIGH TEMPERATURES. 



By Henry B. Hill and Arthur M. Comey. 



Some time ago, at the request of Mr. Alexander Agassiz, President 

 of the Calumet and Hecla Mining Company, one of us studied the 

 behavior of sound and decayed wood at high temperatures, in order to 

 determine the minimum point of ignition of decayed wood, and the 

 lowest temperature at which volatile decomposition products were 

 evolved. Through the kindness of Mr. Agassiz, we are able to present 

 to the Academy the result of the mvestigation. 



I. ON THE MINIMUM POINT OF IGNITION OF 

 DECAYED WOOD. 



By Henry B Hill. 



After a series of preliminary experiments to determine the condi- 

 tions most favorable to ignition and the form of apparatus best adapted 

 to the purpose, I had made a cylindrical air-bath of sheet-iron fitted 

 with a suitable aperture for the admission of air and a short vertical 

 draught pipe, which was sufficient to maintain a free circulation of air 

 when the bath was heated. A horizontal perforated shelf was fixed in 

 the bath, parallel to the axis of the cylinder, and in order to prevent 

 direct radiation or conduction of heat this shelf was covered with a 

 double layer of asbestos paper so arranged as to leave an air space of 

 about five millimeters between the two layers. 



Above the shelf was placed the bulb of the thermometer, and close 

 beside it the sample to be tested. The bulb of the thermometer was 

 further protected from the heat radiated from the sample shortly before 

 ignition by a double screen of asbestos paper. On the upper side of 

 the air bath was cut a rectangular opening closed with a movable 



